GHSA-m99w-x7hq-7vfj
Fix: vercel/next.js#96013GHSA-m99w-x7hq-7vfj is a CWE-834 vulnerability in next. O3 Security confirms whether GHSA-m99w-x7hq-7vfj is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Next.js: Denial of Service in App Router using Server Actions
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-m99w-x7hq-7vfj.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
nextnpmDescription
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next | ≥ 13.0.0&&< 15.5.21 | 15.5.21 |
| 📦npm | next | ≥ 16.0.0&&< 16.2.11 | 16.2.11 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update next to 15.5.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m99w-x7hq-7vfj is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-m99w-x7hq-7vfj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-m99w-x7hq-7vfj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Important: A denial of service flaw exists in Next.js applications utilizing the App Router with Server Actions. Crafted requests can lead to excessive CPU consumption, potentially disrupting service availability for affected Red Hat products that embed or depend on vulnerable Next.js versions.
Frequently Asked Questions
Is GHSA-m99w-x7hq-7vfj in your dependencies?
O3 detects GHSA-m99w-x7hq-7vfj across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.