CVE-2026-25223
HIGHfastify < 5.7.2 - Request Body Validation Bypass via Content-Type Header Tab Injection
Title source: llmDescription
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.
References (6)
Core 6
Core References
Vendor Advisory, Mitigation x_refsource_confirm
https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmq
Patch x_refsource_misc
https://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821
Product, Technical Description x_refsource_misc
https://fastify.dev/docs/latest/Reference/Validation-and-Serialization
Product x_refsource_misc
https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/content-type-parser.js#L125
Product x_refsource_misc
https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/validation.js#L272
Permissions Required x_refsource_misc
https://hackerone.com/reports/3464114
Scores
CVSS v3
7.5
EPSS
0.0052
EPSS Percentile
39.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-436
Status
published
Products (2)
fastify/fastify
< 5.7.2
npm/fastify
0 - 5.7.2npm
Published
Feb 03, 2026
Tracked Since
Feb 18, 2026