HighGHSA-m99w-x7hq-7vfjCVE-2026-64641

Next.js: Denial of Service in App Router using Server Actions

Published 22 Jul 2026 · Updated 10 Sept 2026

Affected packages

nextnpm

Affected: >=13.0.0 <15.5.21
Fixed in: 15.5.21

Update to the fixed version for your release line, for example:npm install next@15.5.21

nextnpm

Affected: >=16.0.0 <16.2.11
Fixed in: 16.2.11

Update to the fixed version for your release line, for example:npm install next@16.2.11

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.

Is GHSA-m99w-x7hq-7vfj in any of your client repos?

Checking one package by hand is fine. Checking it across forty client projects is not. NPMscan reads the lockfiles in every GitHub repo you pick, finds each project with an affected next, and gives you the command that fixes it.

Scan a project free, no signup Or connect GitHub to scan every repo

References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.