Back to CVE records
Medium 4.2Published Oct 19, 2026

CVE-2026-110008@fastify/oauth2 vulnerable to Login CSRF via OAuth state cookie not cleared after callback

Updated under an hour ago ()

Does this affect you?

It affects @fastify/oauth2. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

@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.

CVSS
4.2 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-352, CWE-459, CWE-613
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
openjs
NVD analysis
Awaiting Analysis
Record last updated
Oct 19, 2026
First seen by InfoSec Signals
Oct 19, 2026

Affected products

Affected products
@fastify/oauth2 @fastify/oauth2
fastify_oauth2:fastify_oauth2 (from the name)
from 7.2.0 before 8.3.2; 8.3.2 not affected
CNA record

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

Your cookie choices
We use essential cookies to run this site, and, only with your consent, an advertising cookie from Google to measure whether our ads lead to sign-ups and subscriptions. See our for details.