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Vulnerability record · CVE-2026-33806 · published 15 April 2026

CVE-2026-33806: Fastify vulnerability

Fastify · Fastify

Impact: Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped. This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442 Patches: Upgrade to fastify v5.8.5 or later. Workarounds: None. Upgrade to the patched version.

7.5 CVSS 3.1 High EPSS 0.49% · top 60.7% CWE-1287 · CWE-1287CWE-1289 · CWE-1289
7.5CVSS 3.1 base score
0.49%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
5References
15 Jul 2026Last modified by NVD

Description

Impact: Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped. This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442 Patches: Upgrade to fastify v5.8.5 or later. Workarounds: None. Upgrade to the patched version.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cna.openjsf.org/security-advisories.html Vendor Advisory
https://github.com/fastify/fastify/security/advisories/GHSA-mg2h-6x62-wpwc Not Applicable
https://access.redhat.com/security/cve/CVE-2026-33806
https://bugzilla.redhat.com/show_bug.cgi?id=2458596
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33806.json

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-33806), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.