Description
@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.
Published: 2026-10-19
Score: 4.2 Medium
EPSS: n/a
KEV: No
AI Analysis

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Remediation

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History

Mon, 19 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
Description @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.
Title @fastify/oauth2 vulnerable to Login CSRF via OAuth state cookie not cleared after callback
Weaknesses CWE-352
CWE-459
CWE-613
References
Metrics cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-10-19T13:24:27.988Z

Reserved: 2026-10-13T14:13:40.147Z

Link: CVE-2026-110008

cve-icon Vulnrichment

No data.

cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-352

    Cross-Site Request Forgery (CSRF)

  • CWE-459

    Incomplete Cleanup

  • CWE-613

    Insufficient Session Expiration