High 7.5Published Feb 3, 2026

CVE-2026-25223Fastify's Content-Type header tab character allows body validation bypass

Updated under an hour ago (Oct 27, 2026, 1:10 PM ET)

Does this affect you?

It affects fastify and 3 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for fastify

Exploited in the last 30 days

Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.2, a validation bypass vulnerability exists in Fastify where request body validation schemas specified by Content-Type can be completely circumvented. By appending a tab character (\t) followed by arbitrary content to the Content-Type header, attackers can bypass body validation while the server still processes the body as the original content type. This issue has been patched in version 5.7.2.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-436, CWE-179
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Sep 16, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

fastify fastify fastify:fastify (from the name)	before 5.7.2	CNA record
Red Hat Red Hat OpenShift AI 2.16 redhat:openshift_ai	from 1774282136 not affected	CISA ADP
Red Hat Red Hat OpenShift Dev Spaces 3.27 redhat:openshift_devspaces	from 1774476526 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3 redhat:enterprise_linux_ai	3	CISA ADP
fastify fastify fastify:fastify	before 5.7.2	NVD

References

References

https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmq	x-refsource-confirm, mitigation, vendor-advisory
https://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821	x-refsource-misc, patch
https://hackerone.com/reports/3464114	x-refsource-misc, permissions-required
https://fastify.dev/docs/latest/Reference/Validation-and-Serialization	x-refsource-misc, product, technical-description
https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/content-type-parser.js#L125	x-refsource-misc, product
https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/validation.js#L272	x-refsource-misc, product
https://access.redhat.com/errata/RHSA-2026:10184
https://access.redhat.com/errata/RHSA-2026:5807
https://access.redhat.com/errata/RHSA-2026:6192
https://access.redhat.com/security/cve/CVE-2026-25223
1–10 of 12

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.