What’s Vulnerable › Vulnerabilities

CVE-2026-64646: Next.js: Unbounded Server Action payload in Edge runtime

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-27 · updated 2026-10-24
• Weakness: CWE-770

Description

Next.js is a React framework for building full-stack web applications. In versions 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10, 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. This issue has been fixed in versions 15.5.21 and 16.2.11.

Affected products

• Next.js: from 13.0.0 before 15.5.21; from 16.0.0 before 16.2.11 — fixed in 15.5.21, 16.2.11
• Npm Next: from 13.0.0 before 15.5.21; from 16.0.0 before 16.2.11 — fixed in 15.5.21, 16.2.11

How to fix

Upgrade to a fixed version: Next.js 15.5.21, 16.2.11; Npm Next 15.5.21, 16.2.11. Check the vendor advisory for mitigations.

References

• 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/vercel/next.js/security/advisories/GHSA-4c39-4ccg-62r3

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