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Fencer Vulns
high 7.5

CVE-2026-25223 json

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

published 2026-02-02 9 mo ago modified 2026-09-16 54 d ago also EUVD-2026-5157 , GHSA-jx2c-rxcm-jvmq

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm fastify 5.7.2
  • Red Hat Red Hat OpenShift AI 2.16 1774282136
  • Red Hat Red Hat OpenShift AI 2.25 1776742021, 1776742141
  • Red Hat Red Hat OpenShift Dev Spaces 3.27 1774476526

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-25223 updated cvss 7.5

Fastify: Fastify: Validation bypass due to malformed Content-Type header leading to integrity impact

  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/disk-image-cuda-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-mod-arch-gen-ai-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift AI 2.16 rhoai 1774282136
    fixed: vendor fix RHSA-2026:5807
  • Red Hat OpenShift AI 2.25 rhoai 1776742021, rhoai 1776742141
    fixed: vendor fix RHSA-2026:10184
  • Red Hat OpenShift Dev Spaces 3.27 devspaces 1774476526
    fixed: vendor fix RHSA-2026:6192
  • Red Hat OpenShift AI 2.16 rhoai 1774282058, rhoai 1774282073, rhoai 1774282078, rhoai 1774282087, rhoai 1774282092, rhoai 1774282093, +19 more Red Hat OpenShift AI 2.25 rhoai 1775144403, rhoai 1776243157, rhoai 1776243163, rhoai 1776243192, rhoai 1776243217, rhoai 1776243229, +69 more Red Hat OpenShift Dev Spaces 3.27 devspaces 1773775028, devspaces 1773775064, devspaces 1773775544, devspaces 1774070844, devspaces 1774143680, devspaces 1774155063, +9 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm fastify
<5.7.2
5.7.2

Affected products

  • fastify fastify
  • Red Hat Red Hat OpenShift AI 2.16
  • Red Hat Red Hat OpenShift AI 2.25
  • Red Hat Red Hat OpenShift Dev Spaces 3.27
  • Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3
  • Red Hat Red Hat OpenShift AI (RHOAI)

Classification

Weakness
  • CWE-436 Interpretation Conflict
  • CWE-179 Incorrect Behavior Order: Early Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.