CVE-2026-7768

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

Published May 4, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qxhc-wx3p-2wmg @fastify/accepts-serializer Vulnerable to Denial of Service via Unbounded Accept Header Cache Growth
History
Type Values Removed Values Added
First Time appeared Fastify fastify\/accepts-serializer
CPEs cpe:2.3:a:fastify:fastify\/accepts-serializer:*:*:*:*:*:node.js:*:*
Vendors & Products Fastify fastify\/accepts-serializer
Type Values Removed Values Added
First Time appeared Fastify
Fastify fastify-accepts-serializer
Vendors & Products Fastify
Fastify fastify-accepts-serializer
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title @fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
openjs
Published
Updated
May 4, 2026, 7:50 PM
Reserved
May 4, 2026, 11:50 AM
Status
Analyzed
Published
May 4, 2026, 8:16 PM
Modified
Nov 11, 2026, 11:10 PM