Bug 2555571 (CVE-2026-110008)

Summary: CVE-2026-110008 @fastify/oauth2: @fastify/oauth2: Login CSRF via improper cookie path handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: sdawley
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in @fastify/oauth2. Due to inconsistent cookie path handling during the authentication process, temporary verification cookies are not properly removed after the login flow completes. As a result, single-use authentication tokens persist throughout the user's browser session. A remote attacker can exploit this condition to execute a login Cross-Site Request Forgery (CSRF) attack, forcing a victim's browser to authenticate into an attacker-controlled account.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-10-19 13:32:26 UTC 
@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.