Vulnerability CVE-2023-35935
Published: 2023-07-03

Description:
@fastify/oauth2, a wrapper around the `simple-oauth2` library, is vulnerable to cross site request forgery (CSRF) prior to version 7.2.0.. All versions of @fastify/oauth2 used a statically generated `state` parameter at startup time and were used across all requests for all users. The purpose of the Oauth2 `state` parameter is to prevent CSRF attacks. As such, it should be unique per user and should be connected to the user's session in some way that will allow the server to validate it. Version 7.2.0 changes the default behavior to store the `state` in a cookie with the `http-only` and `same-site=lax` attributes set. The state is now by default generated for every user. Note that this contains a breaking change in the `checkStateFunction` function, which now accepts the full `Request` object. There are no known workarounds for the issue.

Type:

CWE-352

 (Cross-Site Request Forgery (CSRF))

 References:
https://github.com/fastify/fastify-oauth2/commit/bff756b456cbb769080631af2beb85671ff4c79c
https://github.com/fastify/fastify-oauth2/releases/tag/v7.2.0
https://auth0.com/docs/secure/attack-protection/state-parameters
https://github.com/fastify/fastify-oauth2/security/advisories/GHSA-g8x5-p9qc-cf95
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