Update dependency next to v15.5.21 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
next (source)	15.5.20 → 15.5.21

---

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

• https://github.com/vercel/next.js/security/advisories/GHSA-m99w-x7hq-7vfj
• https://github.com/vercel/next.js/pull/96013
• https://github.com/vercel/next.js/commit/019628571641dec57aaf349ba0c360e3964e6f12
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-m99w-x7hq-7vfj

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

• https://github.com/vercel/next.js/security/advisories/GHSA-955p-x3mx-jcvp
• https://github.com/vercel/next.js/commit/1b0c3ae912a3ad925c60065cc8d55b070fa8bcd3
• https://github.com/vercel/next.js/commit/ff12a6124e1504f17b62de948b8a553fdecaef7b
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-955p-x3mx-jcvp

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

• https://github.com/vercel/next.js/security/advisories/GHSA-q8wf-6r8g-63ch
• https://github.com/vercel/next.js/pull/96006
• https://github.com/vercel/next.js/commit/93cb90891402fa4c47798d03cb9e05c13233766c
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-q8wf-6r8g-63ch

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

• https://github.com/vercel/next.js/security/advisories/GHSA-p9j2-gv94-2wf4
• https://github.com/vercel/next.js/commit/35f501357e9b0fe7c950b0d6aa8fcf5343f707e9
• https://github.com/vercel/next.js/commit/d3033266c6dff23f7be71e19341fe3a8c6e2c599
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-p9j2-gv94-2wf4

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

---

Next.js: Unbounded Server Action payload in Edge runtime

CVE-2026-64646 / GHSA-4c39-4ccg-62r3

More information

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://github.com/vercel/next.js/commit/57c31f724d746e86a9e8b92aa8be538a922446a4
• https://github.com/vercel/next.js/commit/9a4651e754f70b12e397694ffc41f44c3ba8cc17
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-4c39-4ccg-62r3

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

• https://github.com/vercel/next.js/security/advisories/GHSA-4633-3j49-mh5q
• https://github.com/vercel/next.js/pull/96008
• https://github.com/vercel/next.js/commit/025bf4a5f7b47fb7758c4ebf1c931a61c451c082
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-4633-3j49-mh5q

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

• https://github.com/vercel/next.js/security/advisories/GHSA-68g3-v927-f742
• https://github.com/vercel/next.js/commit/062f66700b52a5d6bba2c0605d55577ab7ad262c
• https://github.com/vercel/next.js/commit/73b94872bc343d09494b50394d8c08eb9fc8e56a
• https://github.com/vercel/next.js/releases/tag/v15.5.21
• https://github.com/vercel/next.js/releases/tag/v16.2.11
• https://github.com/advisories/GHSA-68g3-v927-f742

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>

---

### 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)

</details>

---

### Configuration

📅 **Schedule**: (UTC)

- Branch creation
  - At any time (no schedule defined)
- Automerge
  - "after 8pm and before 8am every weekday,every weekend"

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/). View the [repository job log](https://developer.mend.io/github/prezly/theme-nextjs-bea).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My42Ni40IiwidXBkYXRlZEluVmVyIjoiNDQuMy4yIiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6W119-->

[renovate]

⚠️ 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

warn: This version of pnpm requires at least Node.js v22.13
warn: The current version of Node.js is v20.20.2
warn: Visit https://r.pnpm.io/comp to see the list of past pnpm versions with respective Node.js version support.
node:internal/modules/cjs/loader:1031
      throw new ERR_UNKNOWN_BUILTIN_MODULE(request);
            ^

Error [ERR_UNKNOWN_BUILTIN_MODULE]: No such built-in module: node:sqlite
    at Module._load (node:internal/modules/cjs/loader:1031:13)
    at Module.require (node:internal/modules/cjs/loader:1289:19)
    at require (node:internal/modules/helpers:182:18)
    at ../store/index/lib/index.js (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:100516:25)
    at __init (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:17:58)
    at ../resolving/npm-resolver/lib/index.js (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:105667:5)
    at __init (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:17:58)
    at ../workspace/projects-graph/lib/index.js (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:105806:5)
    at __init (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:17:58)
    at ../workspace/projects-filter/lib/index.js (file:///opt/containerbase/tools/pnpm/11.18.0/20.20.2/node_modules/pnpm/dist/pnpm.mjs:107210:5) {
  code: 'ERR_UNKNOWN_BUILTIN_MODULE'
}

Node.js v20.20.2

[prezly-quality-agent]

Security update for Next.js looks straightforward. Verify the changelog for any breaking changes between 15.5.12 and 15.5.18.

[prezly-quality-agent]

This is a patch-level security update. Consider checking the Next.js changelog/security advisories to understand what vulnerabilities are being addressed, especially if they affect server-side rendering or API routes which could impact this theme's functionality.