CVE-2026-25223
Fastify's Content-Type header tab character allows body validation bypass
- State
- Published
- Severity
- 7.5 High
- Published
- Feb 3, 2026
- Updated
- Sep 16, 2026
- Reserved
- Jan 30, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | GitHub_M |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
fastifyfastify |
|
References
- https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmq
- https://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821
- https://hackerone.com/reports/3464114
- https://fastify.dev/docs/latest/Reference/Validation-and-Serialization
- https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/content-type-parser.js#L125
- https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/validation.js#L272
- https://access.redhat.com/security/cve/CVE-2026-25223vdb-entry
- RHBZ#2436560issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25223.json
- https://access.redhat.com/errata/RHSA-2026:5807vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10184vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:6192vendor-advisory
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