CVE-2026-7768: fastify fastify\/accepts-serializer

Vulnerability summary

CVE-2026-7768 is a high (CVSS 7.5) vulnerability in fastify fastify\/accepts-serializer. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 40.7% of scored vulnerabilities.

Timeline

1. 04-05-2026
   PublishedVulnerability first disclosed.
2. 04-05-2026
   Last modifiedVulnerability information updated.

Description

@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.

• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.