Tinyauth is an authentication and authorization server. Prior to 5.0.3, the OIDC token endpoint does not verify that the client exchanging an authorization code is the same client the code was issued to. A malicious OIDC client operator can exchange another client's authorization code using their own client credentials, obtaining tokens for users who never authorized their application.
This violates RFC 6749 Section 4.1.3. This vulnerability is fixed in 5.0.3.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 3
https://github.com/steveiliop56/tinyauth/commit/b2a1bfb1f532e87f205fa3afa3fc9f1…
security-advisories@github.com
https://github.com/steveiliop56/tinyauth/releases/tag/v5.0.3
security-advisories@github.com
https://github.com/steveiliop56/tinyauth/security/advisories/GHSA-xg2q-62g2-cvcm
security-advisories@github.com