Next.js: Denial of Service in App Router using Server Actions
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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | next | >= 13.0.0, < 15.5.21, >= 16.0.0, < 16.2.11 | 15.5.21, 16.2.11 |
References
- https://github.com/vercel/next.js/security/advisories/GHSA-m99w-x7hq-7vfj
- https://github.com/vercel/next.js/pull/96013
- https://github.com/vercel/next.js/commit/019628571641dec57aaf349ba0c360e3964e6f12
- https://github.com/vercel/next.js
- https://github.com/vercel/next.js/releases/tag/v15.5.21
- https://github.com/vercel/next.js/releases/tag/v16.2.11
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-834- Platform
- npm
- Package
next- Disclosed
- 22.07.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-m99w-x7hq-7vfj - CC BY 4.0
Vulnerability history: next
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 73
- First → latest
- 12.2017 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 5
- High 27
- Medium 32
- Low 9
Disclosures per year
- 2017: 1
- 2018: 2
- 2019: 0
- 2020: 3
- 2021: 3
- 2022: 3
- 2023: 1
- 2024: 6
- 2025: 14
- 2026: 40
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