CVE-2026-64643
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.
Does this matter?
Lower severity and a low EPSS score (0.52%). Track it; it rarely justifies an emergency change on its own.
Description
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 4.0
- 6.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.52% probability · 42th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-201
- Affected
- vercel/next.js
- Source
- security-advisories@github.com
References
- https://github.com/vercel/next.js/commit/1b0c3ae912a3ad925c60065cc8d55b070fa8bcd3Patch
- https://github.com/vercel/next.js/commit/ff12a6124e1504f17b62de948b8a553fdecaef7bPatch
- https://github.com/vercel/next.js/releases/tag/v15.5.21Product, Release Notes
- https://github.com/vercel/next.js/releases/tag/v16.2.11Product, Release Notes
- https://github.com/vercel/next.js/security/advisories/GHSA-955p-x3mx-jcvpVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.