GHSA-qxhc-wx3p-2wmg
HIGHGHSA-qxhc-wx3p-2wmg is a high-severity (CVSS 7.5) vulnerability in @fastify/accepts-serializer. O3 Security confirms whether GHSA-qxhc-wx3p-2wmg is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
@fastify/accepts-serializer Vulnerable to Denial of Service via Unbounded Accept Header Cache Growth
Blast Radius
@fastify/accepts-serializerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
@fastify/accepts-serializer cached serializer-selection results keyed by the request Accept header without a size limit or eviction policy. A remote unauthenticated client could send many distinct but matching Accept header variants to make the cache grow unbounded. Under sustained load, this can exhaust the Node.js heap and crash the process.
Patches
Update to @fastify/accepts-serializer >= 6.0.4. The cache is now bounded by an LRU with a default size of 100 entries, configurable via the new cacheSize plugin option.
Workarounds
None. Upgrade is required.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @fastify/accepts-serializer | all versions | 6.0.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @fastify/accepts-serializer. 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 @fastify/accepts-serializer to 6.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qxhc-wx3p-2wmg 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-qxhc-wx3p-2wmg 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-qxhc-wx3p-2wmg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-qxhc-wx3p-2wmg in your dependencies?
O3 detects GHSA-qxhc-wx3p-2wmg across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.