CVE-2026-64643Medium▾ SunlitNext.js: Unauthenticated disclosure of internal Server Function endpoints
▾ Sunlit zone — Low / medium · no exploitation signal
impact 27.5 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 28.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.7%
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.
Never assume any authentication claims at the use cache or use server boundary. Always authenticate within the boundary.
next >= 13.0.0, < 15.5.21next >= 16.0.0, < 16.2.11Upgrade to a patched release:
next 15.5.21next 16.2.11Connected by shared product, vendor, weakness, or advisory.
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CVE-2026-64649HighNext.js: Server-Side Request Forgery in Server Actions on custom servers
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CVE-2026-64644MediumNext.js: Denial of Service in the Image Optimization API using SVGs
CVE-2026-64645HighNext.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname
CVE-2026-64646MediumNext.js: Unbounded Server Action payload in Edge runtime