CVE-2026-64643
mediumpriority · track · 21EPSS 0.005 · 43 %ileDEEUUSEPSS · scored 2026-10-27
Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, 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 and Server Actions. By itself, this disclosure is typically a recon/enumeration primitive; however, it can increase risk when combined with other weaknesses. This issue has been fixed in versions 15.5.21 and 16.2.11.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.7–6.3
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (10)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-2468Vercel Next.js: Mehrere SchwachstellenDeutsch2026-07-21csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Vercel Next.js ausnutzen, um Daten zu manipulieren, um Informationen offenzulegen, um einen Denial of Service Angriff durchzuführen, und um Sicherheitsvorkehrungen zu umgehen.
- GHSA-955p-x3mx-jcvpNext.js: Unauthenticated disclosure of internal Server Function endpoints2026-07-22ghsa · osvUS
## 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.
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (10)
External citations — patches, advisories, analysis.
- https://github.com/vercel/next.js/commit/1b0c3ae912a3ad925c60065cc8d55b070fa8bcd3enisa_euvd
- https://github.com/vercel/next.js/commit/ff12a6124e1504f17b62de948b8a553fdecaef7benisa_euvd
- https://github.com/vercel/next.js/releases/tag/v15.5.21enisa_euvd
- https://github.com/vercel/next.js/releases/tag/v16.2.11enisa_euvd
- https://github.com/vercel/next.js/security/advisories/GHSA-955p-x3mx-jcvpenisa_euvd
- https://github.com/vercel/next.js/commit/1b0c3ae912a3ad925c60065cc8d55b070fa8bcd3Patchnvd
- https://github.com/vercel/next.js/commit/ff12a6124e1504f17b62de948b8a553fdecaef7bPatchnvd
- https://github.com/vercel/next.js/releases/tag/v15.5.21ProductRelease Notesnvd
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