CVE-2026-110008
Received
Received - Intake
State Cookie Handling Flaw in Fastify OAuth2
Vulnerability report for CVE-2026-110008, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-19
Last updated on: 2026-10-19
Assigner: openjs
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| @fastify/oauth2 | @fastify/oauth2 | 7.2.0 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-613 | According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization." |
| CWE-352 | The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor. |
| CWE-459 | The product does not properly "clean up" and remove temporary or supporting resources after they have been used. |
