CVE-2026-25223
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data tampering.
- Exploit odds
- 0.9% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.9% in the next 30 days (EPSS).
- Severity: 7.5 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.9% · EPSS, next 30 days
- Weakness
- CWE-436
- Record status
- Modified
Affected
- Fastify < 5.7.2
Attack profile CVSS 3.1 · 7.5
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-25223.md and follow it. Check whether this project is affected by CVE-2026-25223. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821
- https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmq
References
- 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://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821
- https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmq
- https://hackerone.com/reports/3464114
- 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
- https://bugzilla.redhat.com/show_bug.cgi?id=2436560
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25223.json