CVE-2025-68481
Published: 19 December 2025
Summary
CVE-2025-68481 is a medium-severity Improper Authorization (CWE-285) vulnerability in Fastapi-Users Project Fastapi Users. Its CVSS base score is 5.9 (Medium).
Operationally, ranked at the 12.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-204614
Vulnerability details
FastAPI Users allows users to quickly add a registration and authentication system to their FastAPI project. Prior to version 15.0.2, the OAuth login state tokens are completely stateless and carry no per-request entropy or any data that could link them…
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to the session that initiated the OAuth flow. `generate_state_token()` is always called with an empty `state_data` dict, so the resulting JWT only contains the fixed audience claim plus an expiration timestamp. On callback, the library merely checks that the JWT verifies under `state_secret` and is unexpired; there is no attempt to match the state value to the browser that initiated the OAuth request, no correlation cookie, and no server-side cache. Any attacker can hit `/authorize`, capture the server-generated state, finish the upstream OAuth flow with their own provider account, and then trick a victim into loading `.../callback?code=<attacker_code>&state=<attacker_state>`. Because the state JWT is valid for any client for \~1 hour, the victim’s browser will complete the flow. This leads to login CSRF. Depending on the app’s logic, the login CSRF can lead to an account takeover of the victim account or to the victim user getting logged in to the attacker's account. Version 15.0.2 contains a patch for the issue.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Documented procedures facilitate correct implementation and ongoing management of authorization decisions.
Periodic reviews identify and correct flaws in authorization decisions or enforcement.
The control's documentation requirement reduces improper authorization by ensuring only mission-justified actions bypass authentication.
Establishing permitted attributes and values, plus auditing changes, ensures authorization decisions are based on correctly managed policy data.
Explicitly mandates authorizing remote access types before permitting connections, directly mitigating improper authorization.
The control explicitly requires authorization of each wireless access type prior to permitting connections.
Mandating explicit authorization of mobile device connections reduces the risk of improper authorization decisions for system access.
Specifying access authorizations for each account and requiring approvals for account requests enforces proper authorization decisions.