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Fencer Intel
medium 4.2

CVE-2026-110008 json

@fastify/oauth2 vulnerable to Login CSRF via OAuth state cookie not cleared after callback

published 21d ago modified 21d ago also EUVD-2026-104327

cvss
4.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 0%
public exploits
0
none known

Summary

@fastify/oauth2 is a Fastify wrapper for OAuth2 login flows. In versions 7.2.0 through 8.3.1, the state and code-verifier cookies are set without a Path attribute at a login route with two or more path segments, while the clearing step at the OAuth callback writes them with a root path, so the original cookies survive the callback and the documented single-use guarantee for the state value does not hold. A state value an attacker learns stays valid for the rest of the browser session, letting the attacker drive their own authorization flow in the victim's browser and sign the victim in to the attacker's account (login CSRF). The issue is fixed in @fastify/oauth2 8.3.2, and users should upgrade to 8.3.2 or later. As a workaround, set an explicit cookie path so the set and the clear name the same cookie.

Patch / fix

  • @fastify/oauth2 @fastify/oauth2 8.3.2

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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-2026-110008 updated cvss 4.2

@fastify/oauth2: @fastify/oauth2: Login CSRF via improper cookie path handling

  • Red Hat OpenShift Dev Spaces devspaces/dashboard-rhel9
    affected: workaround, no fix available “Upgrade @fastify/oauth2 to 8.3.2 in devspaces/dashboard-rhel9, or apply upstream workaround (explicit cookie path 'cookie:{path:"/"}', hostPrefixedCookies:true, or single-segment startRedirectPath).”

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
21d ago

Exploit prediction

0.10% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected products

  • @fastify/oauth2 @fastify/oauth2

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery
  • CWE-459 Incomplete Cleanup
  • CWE-613 DEPRECATED: Insufficient Session Expiration

References

Sources

Fencer Intel 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.