Denial of Service Vulnerability in next.js
Published 28 Jan 2022 · Updated 10 Sept 2026
Affected package
- Affected
- >=12.0.0 <12.0.9
- Fixed in
- 12.0.9
npm install next@12.0.9Details
Impact
Vulnerable code could allow a bad actor to trigger a denial of service attack for anyone running a Next.js app at version >= 12.0.0, and using i18n functionality.
- Affected: All of the following must be true to be affected by this CVE
- Next.js versions above v12.0.0
- Using next start or a custom server
- Using the built-in i18n support
- Not affected:
- Deployments on Vercel (vercel.com) are not affected along with similar environments where invalid requests are filtered before reaching Next.js.
Patches
A patch has been released, next@12.0.9, that mitigates this issue. We recommend all affected users upgrade as soon as possible.
Workarounds
We recommend upgrading whether you can reproduce or not although you can ensure /${locale}/_next/ is blocked from reaching the Next.js instance until you upgrade.
For more information
If you have any questions or comments about this advisory:
- Open an issue in next
- Email us at [security@vercel.com](mailto:security@vercel.com)
Is GHSA-wr66-vrwm-5g5x 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.
References
Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.