Description

@fastify/accepts-serializer Vulnerable to Denial of Service via Unbounded Accept Header Cache Growth

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.

Mitigation

Aliases

References