oauth CSRF vulnerability

Vulnerability Description

In the OAuth library for nim prior to version 0.11, the Authorization Code grant and Implicit grant both rely on the `state` parameter to prevent cross-site request forgery (CSRF) attacks where a resource owner might have their session associated with protected resources belonging to an attacker. When this project is compiled with certain compiler flags set, it is possible that the `state` parameter will not be checked at all, creating a CSRF vulnerability. Version 0.11 checks the `state` parameter using a regular `if` statement or `doAssert` instead of relying on a plain `assert`. `doAssert` will achieve the desired behavior even if `-d:danger` or `--assertions:off` is set.

References

• https://github.com/CORDEA/oauth/security/advisories/GHSA-pc9j-53g7-5x54
• https://github.com/CORDEA/oauth/blob/b8c163b0d9cfad6d29ce8c1fb394e5f47182ee1c/src/oauth2.nim#L235
• https://github.com/CORDEA/oauth/blob/b8c163b0d9cfad6d29ce8c1fb394e5f47182ee1c/src/oauth2.nim#L255