chore(repo): Update dependency next to v15.5.21 [SECURITY] by renovate[bot] · Pull Request #9559 · clerk/javascript

renovate · 2026-08-26T09:55:44Z

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
next (source)	`15.5.19` → `15.5.21`

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Next.js self-hosted applications vulnerable to DoS via Image Optimizer remotePatterns configuration

CVE-2025-59471 / GHSA-9g9p-9gw9-jx7f

More information

Details

A DoS vulnerability exists in self-hosted Next.js applications that have remotePatterns configured for the Image Optimizer. The image optimization endpoint (/_next/image) loads external images entirely into memory without enforcing a maximum size limit, allowing an attacker to cause out-of-memory conditions by requesting optimization of arbitrarily large images. This vulnerability requires that remotePatterns is configured to allow image optimization from external domains and that the attacker can serve or control a large image on an allowed domain.

Strongly consider upgrading to 15.5.10 and 16.1.5 to reduce risk and prevent availability issues in Next applications.

Severity

CVSS Score: 5.9 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js HTTP request deserialization can lead to DoS when using insecure React Server Components

GHSA-h25m-26qc-wcjf

More information

Details

A vulnerability affects certain React Server Components packages for versions 19.0.x, 19.1.x, and 19.2.x and frameworks that use the affected packages, including Next.js 13.x, 14.x, 15.x, and 16.x using the App Router. The issue is tracked upstream as CVE-2026-23864.

A specially crafted HTTP request can be sent to any App Router Server Function endpoint that, when deserialized, may trigger excessive CPU usage, out-of-memory exceptions, or server crashes. This can result in denial of service in unpatched environments.

Severity

CVSS Score: 7.5 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: HTTP request smuggling in rewrites

CVE-2026-29057 / GHSA-ggv3-7p47-pfv8

More information

Details

Summary

When Next.js rewrites proxy traffic to an external backend, a crafted DELETE/OPTIONS request using Transfer-Encoding: chunked could trigger request boundary disagreement between the proxy and backend. This could allow request smuggling through rewritten routes.

Impact

An attacker could smuggle a second request to unintended backend routes (for example, internal/admin endpoints), bypassing assumptions that only the configured rewrite destination/path is reachable. This does not impact applications hosted on providers that handle rewrites at the CDN level, such as Vercel.

Patches

The vulnerability originated in an upstream library vendored by Next.js. It is fixed by updating that dependency’s behavior so content-length: 0 is added only when both content-length and transfer-encoding are absent, and transfer-encoding is no longer removed in that code path.

Workarounds

If upgrade is not immediately possible:

Block chunked DELETE/OPTIONS requests on rewritten routes at your edge/proxy.
Enforce authentication/authorization on backend routes per our security guidance.

Severity

CVSS Score: 6.3 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Unbounded next/image disk cache growth can exhaust storage

CVE-2026-27980 / GHSA-3x4c-7xq6-9pq8

More information

Details

Summary

The default Next.js image optimization disk cache (/_next/image) did not have a configurable upper bound, allowing unbounded cache growth.

Impact

An attacker could generate many unique image-optimization variants and exhaust disk space, causing denial of service. Note that this does not impact platforms that have their own image optimization capabilities, such as Vercel.

Patches

Fixed by adding an LRU-backed disk cache with images.maximumDiskCacheSize, including eviction of least-recently-used entries when the limit is exceeded. Setting maximumDiskCacheSize: 0 disables disk caching.

Workarounds

If upgrade is not immediately possible:

Periodically clean .next/cache/images.
Reduce variant cardinality (e.g., tighten values for images.localPatterns, images.remotePatterns, and images.qualities)

Severity

CVSS Score: 6.9 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js has a Denial of Service with Server Components

GHSA-q4gf-8mx6-v5v3

More information

Details

A vulnerability affects certain React Server Components packages for versions 19.x and frameworks that use the affected packages, including Next.js 13.x, 14.x, 15.x, and 16.x using the App Router. The issue is tracked upstream as CVE-2026-23869. You can read more about this advisory our this changelog.

A specially crafted HTTP request can be sent to any App Router Server Function endpoint that, when deserialized, may trigger excessive CPU usage. This can result in denial of service in unpatched environments.

Severity

CVSS Score: 7.5 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js Vulnerable to Denial of Service with Server Components

GHSA-8h8q-6873-q5fj

More information

Details

A vulnerability affects certain React Server Components packages for versions 19.x and frameworks that use the affected packages, including Next.js 13.x, 14.x, 15.x, and 16.x using the App Router. The issue is tracked upstream as CVE-2026-23870.

A specially crafted HTTP request can be sent to any App Router Server Function endpoint that, when deserialized, may trigger excessive CPU usage. This can result in denial of service in unpatched environments.

Severity

CVSS Score: 7.5 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js has a Middleware / Proxy bypass in Pages Router applications using i18n

CVE-2026-44573 / GHSA-36qx-fr4f-26g5

More information

Details

Impact

Applications using the Pages Router with i18n configured and middleware/proxy-based authorization can allow unauthorized access to protected page data through locale-less /_next/data/<buildId>/<page>.json requests. In affected configurations, middleware does not run for the unprefixed data route, allowing an attacker to retrieve SSR JSON for protected pages without passing the intended authorization checks.

Fix

The matcher logic was updated to perform the same match as it would on a non-i18n data route.

Workarounds

If you cannot upgrade immediately, enforce authorization in the page's server-side data path instead of relying solely on middleware.

Severity

CVSS Score: 7.5 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js vulnerable to server-side request forgery in applications using WebSocket upgrades

CVE-2026-44578 / GHSA-c4j6-fc7j-m34r

More information

Details

Impact

Self-hosted applications using the built-in Node.js server can be vulnerable to server-side request forgery through crafted WebSocket upgrade requests. An attacker can cause the server to proxy requests to arbitrary internal or external destinations, which may expose internal services or cloud metadata endpoints. Vercel-hosted deployments are not affected.

Fix

We now apply the same safety checks to WebSocket upgrade handling that already existed for normal HTTP requests, so upgrade requests are only proxied when routing has explicitly marked them as safe external rewrites.

Workarounds

If you cannot upgrade immediately, do not expose the origin server directly to untrusted networks. If WebSocket upgrades are not required, block them at your reverse proxy or load balancer, and restrict origin egress to internal networks and metadata services where possible.

Severity

CVSS Score: 8.6 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js has a Denial of Service in the Image Optimization API

CVE-2026-44577 / GHSA-h64f-5h5j-jqjh

More information

Details

Impact

When self-hosting Next.js with the default image loader, the Image Optimization API fetches local images entirely into memory without enforcing a maximum size limit. An attacker could cause out-of-memory conditions by requesting large local assets from the /_next/image endpoint that match the images.localPatterns configuration (by default, all patterns are allowed).

If you are using images.localPatterns, only the patterns in that array are impacted.
If you are using images.unoptimized: true, you are NOT impacted.
If you are using images.loader: 'custom', you are NOT impacted.
If you are using Vercel, you are NOT impacted.

Fix

We now apply response size limits consistently to internal image fetches, not just external ones, and fail oversized responses before they can exhaust process memory.

This can be adjusted using the images.maximumResponseBody configuration.

Workarounds

If you cannot upgrade immediately, avoid routing large local assets through /_next/image, disable image optimization for large or untrusted local files, or block image optimization access to those assets at the edge.

You can disable using the images.localPatterns: [] configuration. This will still allow fetching remote images (which is not impacted).

Severity

CVSS Score: 5.9 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js has cross-site scripting in beforeInteractive scripts with untrusted input

CVE-2026-44580 / GHSA-gx5p-jg67-6x7h

More information

Details

Impact

Applications that use beforeInteractive scripts together with untrusted content can be vulnerable to cross-site scripting. In affected versions, serialized script content was not escaped safely before being embedded into the document, which could allow attacker-controlled input to break out of the intended script context and execute arbitrary JavaScript in a visitor's browser.

Fix

We now HTML-escape serialized beforeInteractive script content before embedding it into the page, preventing attacker-controlled content from breaking out of the inline script boundary.

Workarounds

If you cannot upgrade immediately, do not pass untrusted data into beforeInteractive scripts. If that pattern is unavoidable, sanitize or escape the content before embedding it.

Severity

CVSS Score: 6.1 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js vulnerable to cache poisoning via collisions in React Server Component cache-busting

CVE-2026-44582 / GHSA-vfv6-92ff-j949

More information

Details

Impact

React Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the _rsc cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL.

Fix

We strengthened the _rsc cache-busting mechanism to make practical collisions significantly harder and to better separate response variants that should not share cache entries.

Workarounds

If you cannot upgrade immediately, ensure intermediary caches correctly honor Vary for RSC-related request headers, or disable shared caching for affected RSC responses until you can deploy a patched release.

Severity

CVSS Score: 3.7 / 10 (Low)
Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js vulnerable to cross-site scripting in App Router applications using CSP nonces

CVE-2026-44581 / GHSA-ffhc-5mcf-pf4q

More information

Details

Impact

App Router applications that rely on CSP nonces can be vulnerable to stored cross-site scripting when deployed behind shared caches. In affected versions, malformed nonce values derived from request headers could be reflected into rendered HTML in an unsafe way, allowing an attacker to poison cached responses and cause script execution for later visitors.

Fix

We now reject or ignore malformed nonce values before they are embedded into HTML and apply stricter nonce sanitization so request-derived nonce data cannot break out of the intended attribute context.

Workarounds

If you cannot upgrade immediately, strip inbound Content-Security-Policy request headers from untrusted traffic.

Severity

CVSS Score: 4.7 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js's Middleware / Proxy redirects can be cache-poisoned

CVE-2026-44572 / GHSA-3g8h-86w9-wvmq

More information

Details

Impact

Next.js uses the x-nextjs-data request header for internal data requests. On affected versions, an external client could send this header on a normal request to a path handled by middleware that returns a redirect.

When that happened, the middleware/proxy could treat the request as a data request and replace the standard Location redirect header with the internal x-nextjs-redirect header. Browsers do not follow x-nextjs-redirect, so the response became an unusable redirect for normal clients.

If the application was deployed behind a CDN or reverse proxy that caches 3xx responses without varying on this header, a single attacker request could poison the cached redirect response for the affected path. Subsequent visitors could then receive a cached redirect response without a Location header, causing a denial of service for that redirect path until the cache entry expired or was purged.

Affected scenarios

This affects applications that:

use middleware or proxy redirects
are deployed behind a caching CDN or reverse proxy
allow 3xx responses on those paths to be cached without differentiating internal data requests from normal requests

Fix

The fix stops trusting x-nextjs-data by itself for middleware redirect handling. A request is now treated as an internal data request only when it is validated as such by internal routing state, preserving legitimate data-request redirect behavior while preventing external header injection from changing normal redirect responses.

Workarounds

Before upgrading, users can reduce risk by:

configuring the CDN or reverse proxy to vary its cache key on x-nextjs-data for affected responses

Severity

CVSS Score: 3.7 / 10 (Low)
Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Denial of Service in App Router using Server Actions

CVE-2026-64641 / GHSA-m99w-x7hq-7vfj

More information

Details

Impact

Crafted requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive CPU usage blocking processing of further requests in the same process.

Workarounds

No workaround exists besides upgrading. Applications using Pages Router or not using Server Actions are not vulnerable.

Severity

CVSS Score: 8.2 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Unauthenticated disclosure of internal Server Function endpoints

CVE-2026-64643 / GHSA-955p-x3mx-jcvp

More information

Details

Impact

In Next.js applications using App Router, Server Actions (use server) or use cache endpoints can be disclosed bypassing any authentication on the pages where these endpoints are usually used.

Server Action IDs can be disclosed to unauthenticated users via publicly served client artifacts (for example, static chunks containing action references).

Affected users are applications using App Router + Server Actions.

By itself, this disclosure is typically a recon/enumeration primitive; however, it can increase risk when combined with other weaknesses.

Workarounds

Never assume any authentication claims at the use cache or use server boundary. Always authenticate within the boundary.

Severity

CVSS Score: 6.3 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Denial of Service in the Image Optimization API using SVGs

CVE-2026-64644 / GHSA-q8wf-6r8g-63ch

More information

Details

Impact

When self-hosting Next.js with the default image loader, the Image Optimization API can optimize remotely hosted images if configured (not enabled by default). If those images contain malicious content, they can cause CPU exhaustion in /_next/image endpoints.

If you are using config.images.remotePatterns, only the patterns in that array are impacted.
If you are using config.images.unoptimized: true, you are NOT impacted.
If you are using config.images.loader: 'custom', you are NOT impacted.
If you are using Vercel, you are NOT impacted.

Workarounds

If you cannot upgrade immediately, you can avoid the expensive work by setting config.experimental.imgOptSkipMetadata : true.

Severity

CVSS Score: 6.3 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname

CVE-2026-64645 / GHSA-p9j2-gv94-2wf4

More information

Details

Impact

A rewrites() or redirects() rule that builds its external destination hostname from request-controlled input can be pointed at an arbitrary hostname, regardless of the rule's hostname suffix. For a rewrite, Next.js proxies the request to that arbitrary host and serves the response from the application's origin, leading to Server-Side Request forgery. A redirects() rule configured this way is vulnerable to an Open Redirect.

This affects any destination that puts a dynamic segment in the hostname, whether from the path:

// next.config.js
module.exports = {
  async rewrites() {
    return [
      {
        source: '/:tenant',
        destination: 'https://:tenant.api.example.com',
      },
    ]
  },
}

or from a has capture:

// next.config.js
module.exports = {
  async rewrites() {
    return [
      {
        source: '/',
        has: [{ type: 'query', key: 'region', value: '(?<region>.+)' }],
        destination: 'https://:region.api.example.com',
      },
    ]
  },
}

Workarounds

If you cannot upgrade immediately, do not build the hostname of an external rewrites() or redirects() destination from user-controlled input. If a dynamic subdomain is required, constrain the value to hostname-safe characters: value: '(?<region>[a-z0-9-]+)'.

Severity

CVSS Score: 8.3 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/SI:L/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences

CVE-2026-64647 / GHSA-4633-3j49-mh5q

More information

Details

Impact

A server-side fetch with a request body may return a cached response body from a different request to the same URL but different body. Confidential data in the POST's response body would then leak to unauthorized requests. Though the request itself will not be deduped.

This is only an issue when receiving request bodies with a content type charset other than UTF-8. For example, the UTF-16 byte sequences for 삃삃 and 섄섄 in the request body would share the same cache.

Workarounds

If you cannot upgrade, consider only making fetch requests with UTF-8 bodies (default in Next.js). Applications using Pages Router are not vulnerable.

Severity

CVSS Score: 6.3 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Cache confusion of response bodies for requests with bodies

CVE-2026-64648 / GHSA-68g3-v927-f742

More information

Details

Impact

A server-side fetch with a request body may return a cached response body from a different request to the same URL but different body. Confidential data in the POST's response body would then leak to unauthorized requests. Though the request itself will not be deduped.

This only applies to fetch calls with a request that has a different init than the one passed to fetch.
Safe: fetch(new Request(init), init)
Unsafe: fetch(new Request(init), aDifferentInit)

Workarounds

No workaround exists besides upgrading. Applications using Pages Router are not vulnerable.

Severity

CVSS Score: 6.0 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Next.js: Server-Side Request Forgery in Server Actions on custom servers

CVE-2026-64649 / GHSA-89xv-2m56-2m9x

More information

Details

Impact

When a Server Action forwards or redirects a request, an attacker can cause the server to send that outbound request to a malicious host (Server-Side Request Forgery). This requires the attacker's request to control Host-associated headers. In some configurations, it's also possible to obtain internal values that weaken middleware/proxy authorization.

Applications that use Server Actions are affected when the incoming host header is not fixed to a trusted value. This typically occurs on custom servers, or on deployments not behind a proxy that pins the host. Managed hosting pins the host upstream and is not affected; next start and standalone output do the same from version 14.2 onward.

Workarounds

If you cannot upgrade, ensure clients do not control the host header your application receives. Pin or validate Host and X-Forwarded-Host at your edge or proxy. On version 14.2.0 and later, you can additionally set the __NEXT_PRIVATE_ORIGIN environment variable to your deployment's real origin:

__NEXT_PRIVATE_ORIGIN=https://www.example.com node server.js

#### Severity
- CVSS Score: 8.3 / 10 (High)
- Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`

#### References
- [https://github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x](https://redirect.github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x)
- [https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b](https://redirect.github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b)
- [https://github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498](https://redirect.github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498)
- [https://github.com/vercel/next.js/releases/tag/v15.5.21](https://redirect.github.com/vercel/next.js/releases/tag/v15.5.21)
- [https://github.com/vercel/next.js/releases/tag/v16.2.11](https://redirect.github.com/vercel/next.js/releases/tag/v16.2.11)
- [https://github.com/advisories/GHSA-89xv-2m56-2m9x](https://redirect.github.com/advisories/GHSA-89xv-2m56-2m9x)

This data is provided by the [GitHub Advisory Database](https://redirect.github.com/advisories/GHSA-89xv-2m56-2m9x) ([CC-BY 4.0](https://redirect.github.com/github/advisory-database/blob/main/LICENSE.md)).
</details>

---

### Next.js: Unbounded Server Action payload in Edge runtime
[CVE-2026-64646](https://nvd.nist.gov/vuln/detail/CVE-2026-64646) / [GHSA-4c39-4ccg-62r3](https://redirect.github.com/advisories/GHSA-4c39-4ccg-62r3)

<details>
<summary>More information</summary>

#### Details
##### Impact

Requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive memory consumption if that Server Actions uses the Edge runtime

##### Workarounds

If you cannot upgrade, ensure your hosting provider limits the request's body size. 5 MiB should be allowed at max by your hosting provider.

#### Severity
- CVSS Score: 6.3 / 10 (Medium)
- Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`

#### References
- [https://github.com/vercel/next.js/security/advisories/GHSA-4c39-4ccg-62r3](https://redirect.github.com/vercel/next.js/security/advisories/GHSA-4c39-4ccg-62r3)
- [https://github.com/vercel/next.js/commit/57c31f724d746e86a9e8b92aa8be538a922446a4](https://redirect.github.com/vercel/next.js/commit/57c31f724d746e86a9e8b92aa8be538a922446a4)
- [https://github.com/vercel/next.js/commit/9a4651e754f70b12e397694ffc41f44c3ba8cc17](https://redirect.github.com/vercel/next.js/commit/9a4651e754f70b12e397694ffc41f44c3ba8cc17)
- [https://github.com/vercel/next.js/releases/tag/v15.5.21](https://redirect.github.com/vercel/next.js/releases/tag/v15.5.21)
- [https://github.com/vercel/next.js/releases/tag/v16.2.11](https://redirect.github.com/vercel/next.js/releases/tag/v16.2.11)
- [https://github.com/advisories/GHSA-4c39-4ccg-62r3](https://redirect.github.com/advisories/GHSA-4c39-4ccg-62r3)

This data is provided by the [GitHub Advisory Database](https://redirect.github.com/advisories/GHSA-4c39-4ccg-62r3) ([CC-BY 4.0](https://redirect.github.com/github/advisory-database/blob/main/LICENSE.md)).
</details>

---

### Release Notes

<details>
<summary>vercel/next.js (next)</summary>

### [`v15.5.21`](https://redirect.github.com/vercel/next.js/compare/v15.5.20...v15.5.21)

[Compare Source](https://redirect.github.com/vercel/next.js/compare/v15.5.20...v15.5.21)

### [`v15.5.20`](https://redirect.github.com/vercel/next.js/releases/tag/v15.5.20)

[Compare Source](https://redirect.github.com/vercel/next.js/compare/v15.5.19...v15.5.20)

Contains no changes except publishing `@next/swc-wasm-web` which was accidentally not published since 15.5.15.

</details>

---

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---

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<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0NC40Ni4wIiwidXBkYXRlZEluVmVyIjoiNDQuNDYuMCIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOlsiZGVwZW5kZW5jaWVzIl19-->

renovate · 2026-08-26T09:55:48Z

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

any of the package files in this branch needs updating, or
the branch becomes conflicted, or
you click the rebase/retry checkbox if found above, or
you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: pnpm-lock.yaml


<--- Last few GCs --->

[979:0xecc6000]   111360 ms: Scavenge 1478.8 (1494.1) -> 1476.8 (1495.4) MB, pooled: 0 MB, 14.28 / 0.01 ms  (average mu = 0.369, current mu = 0.394) allocation failure; 
[979:0xecc6000]   113215 ms: Mark-Compact (reduce) 1478.0 (1495.4) -> 1469.9 (1478.9) MB, pooled: 0 MB, 1480.94 / 0.01 ms  (+ 348.9 ms in 18 steps since start of marking, biggest step 23.4 ms, walltime since start of marking 1855 ms) (average mu = 0.367, 
FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
----- Native stack trace -----

 1: 0x73f8c4 node::OOMErrorHandler(char const*, v8::OOMDetails const&) [/opt/containerbase/tools/node/24.15.0/bin/node]
 2: 0xc06f90  [/opt/containerbase/tools/node/24.15.0/bin/node]
 3: 0xc0707f  [/opt/containerbase/tools/node/24.15.0/bin/node]
 4: 0xeaa885  [/opt/containerbase/tools/node/24.15.0/bin/node]
 5: 0xeaa8b2  [/opt/containerbase/tools/node/24.15.0/bin/node]
 6: 0xeaabaa  [/opt/containerbase/tools/node/24.15.0/bin/node]
 7: 0xebb8aa  [/opt/containerbase/tools/node/24.15.0/bin/node]
 8: 0xebfc50  [/opt/containerbase/tools/node/24.15.0/bin/node]
 9: 0x1953f71  [/opt/containerbase/tools/node/24.15.0/bin/node]
/usr/local/bin/node: line 18:   979 Aborted                 /opt/containerbase/tools/node/24.15.0/bin/node "$@"

vercel · 2026-08-26T09:55:51Z

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
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swingset	Ready	Preview	Aug 27, 2026 10:55pm

changeset-bot · 2026-08-26T09:55:52Z

⚠️ No Changeset found

Latest commit: 417110d

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

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Renovate's artifact update OOM'd, so the branch had the package.json bump without the lockfile. Claude-Session: https://claude.ai/code/session_01Fovsdti3tG61y2Gm46Wnpm

Claude-Session: https://claude.ai/code/session_01Fovsdti3tG61y2Gm46Wnpm

pkg-pr-new · 2026-08-27T19:52:30Z

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@clerk/astro

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@clerk/backend

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@clerk/chrome-extension

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@clerk/clerk-js

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@clerk/electron

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@clerk/electron-passkeys

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@clerk/expo-google-signin

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@clerk/expo-passkeys

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@clerk/express

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@clerk/fastify

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@clerk/hono

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@clerk/localizations

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@clerk/nextjs

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@clerk/nuxt

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@clerk/react

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@clerk/react-router

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@clerk/shared

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@clerk/ui

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@clerk/upgrade

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@clerk/vue

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commit: 417110d

github-actions · 2026-08-27T19:53:17Z

API Changes Report

Generated by Break Check on 2026-08-27T22:56:26.786Z

Summary

Metric	Count
Packages analyzed	19
Packages with changes	0
🔴 Breaking changes	0
🟡 Non-breaking changes	0
🟢 Additions	0

No API Changes Detected

All packages have stable APIs with no detected changes.

Report generated by Break Check

_{Last ran on 417110d.}

renovate · 2026-08-27T20:00:50Z

Edited/Blocked Notification

Renovate will not automatically rebase this PR, because it does not recognize the last commit author and assumes somebody else may have edited the PR.

You can manually request rebase by checking the rebase/retry box above.

⚠️ Warning: custom changes will be lost.

The next and hono updates only raise devDependency floors, so they do not change published package behavior and do not need a release. Claude-Session: https://claude.ai/code/session_01PEDVeaJ5AS6QZzxrh67YWb

renovate Bot added the dependencies Pull requests that update a dependency file label Aug 26, 2026

vercel Bot had a problem deploying to Preview – clerk-js-sandbox August 26, 2026 09:55 Failure

vercel Bot had a problem deploying to Preview – swingset August 26, 2026 09:55 Failure

github-actions Bot added the nextjs label Aug 26, 2026

renovate Bot force-pushed the renovate/npm-next-vulnerability branch from 2654e7f to 18097d3 Compare August 27, 2026 18:46

vercel Bot had a problem deploying to Preview – clerk-js-sandbox August 27, 2026 18:46 Failure

vercel Bot had a problem deploying to Preview – swingset August 27, 2026 18:46 Failure

chore(repo): Update dependency next to v15.5.21 [SECURITY]

424db9d

renovate Bot force-pushed the renovate/npm-next-vulnerability branch from 18097d3 to 424db9d Compare August 27, 2026 19:45

vercel Bot had a problem deploying to Preview – clerk-js-sandbox August 27, 2026 19:45 Failure

vercel Bot had a problem deploying to Preview – swingset August 27, 2026 19:45 Failure

chore(nextjs): regenerate lockfile for next 15.5.21 and add changeset

5ea0343

Renovate's artifact update OOM'd, so the branch had the package.json bump without the lockfile. Claude-Session: https://claude.ai/code/session_01Fovsdti3tG61y2Gm46Wnpm

vercel Bot deployed to Preview – clerk-js-sandbox August 27, 2026 19:47 View deployment

chore(nextjs): dedupe next to 15.5.21 across workspace

aaf0a62

Claude-Session: https://claude.ai/code/session_01Fovsdti3tG61y2Gm46Wnpm

vercel Bot temporarily deployed to Preview – clerk-js-sandbox August 27, 2026 19:48 Inactive

vercel Bot deployed to Preview – swingset August 27, 2026 19:51 View deployment

wobsoriano approved these changes Aug 27, 2026

View reviewed changes

chore(repo): Remove changesets for devDependency-only security bumps

417110d

The next and hono updates only raise devDependency floors, so they do not change published package behavior and do not need a release. Claude-Session: https://claude.ai/code/session_01PEDVeaJ5AS6QZzxrh67YWb

vercel Bot deployed to Preview – clerk-js-sandbox August 27, 2026 22:53 View deployment

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chore(repo): Update dependency next to v15.5.21 [SECURITY] - #9559

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renovate Bot commented Aug 26, 2026

Next.js self-hosted applications vulnerable to DoS via Image Optimizer remotePatterns configuration

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Next.js HTTP request deserialization can lead to DoS when using insecure React Server Components

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Next.js: HTTP request smuggling in rewrites

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Next.js: Unbounded next/image disk cache growth can exhaust storage

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Next.js has a Denial of Service with Server Components

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Next.js Vulnerable to Denial of Service with Server Components

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Next.js has a Middleware / Proxy bypass in Pages Router applications using i18n

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Next.js vulnerable to server-side request forgery in applications using WebSocket upgrades

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Next.js has a Denial of Service in the Image Optimization API

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Next.js has cross-site scripting in beforeInteractive scripts with untrusted input

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Next.js vulnerable to cache poisoning via collisions in React Server Component cache-busting

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Next.js vulnerable to cross-site scripting in App Router applications using CSP nonces

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Next.js's Middleware / Proxy redirects can be cache-poisoned

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