fastify accepts-serializer up to 6.0.3 allocation of resources

Summaryinfo

A vulnerability was found in fastify accepts-serializer up to 6.0.3. It has been classified as problematic. This impacts an unknown function. This manipulation causes allocation of resources. This vulnerability is handled as CVE-2026-7768. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in fastify accepts-serializer up to 6.0.3. It has been declared as problematic. Affected by this vulnerability is an unknown code block. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. The summary by CVE is:

@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.

The weakness was released by Yuki Matsuhashi as GHSA-qxhc-wx3p-2wmg. It is possible to read the advisory at cna.openjsf.org. This vulnerability is known as CVE-2026-7768 since 05/04/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 6.0.4 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-27131). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• fastify

Name

• accepts-serializer

Version

• 6.0.0
• 6.0.1
• 6.0.2
• 6.0.3

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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