CVE-2026-7768

@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, eventually exhausting the Node.js heap and crashing the process. Versions <= 6.0.3 are affected. Update to 6.0.4 or later, which bounds the cache via an LRU with a default size of 100 entries, configurable through the new cacheSize plugin option.

• https://cna.openjsf.org/security-advisories.html
• https://github.com/fastify/fastify-accepts-serializer/security/advisories/GHSA-qxhc-wx3p-2wmg