CVE-2026-7768 | @fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth

@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.

Published: 2026-05-04 Last update: 2026-05-29 Assigner: ce714d77-add3-4f53-aff5-83d477b104bb Source: ce714d77-add3-4f53-aff5-83d477b104bb
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-7768 is rated Low Risk (35.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-7768

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-30 0.05% 0.05% -0.00%
2 2026-05-10 0.04% 0.05% +0.01%
3 2026-05-05 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-7768

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 ce714d77-add3-4f53-aff5-83d477b104bb

Weakness enumeration for CVE-2026-7768

GitHub Security Advisory for CVE-2026-7768

GHSA-qxhc-wx3p-2wmg · Severity: high · Ecosystem: npm — @fastify/accepts-serializer Vulnerable to Denial of Service via Unbounded Accept Header Cache Growth

Affected software / configurations for CVE-2026-7768

Vendor Product Version Raw CPE
fastify fastify\/accepts-serializer < 6.0.4 cpe:2.3:a:fastify:fastify\/accepts-serializer:*:*:*:*:*:node.js:*:*

References for CVE-2026-7768

cvelogic Threat Intelligence