CVE-2025-14546Medium· 6.3▾ SunlitFastAPI SSP is vulnerable to Cross-site Request Forgery (CSRF) through improper OAuth parameter validation
▾ Sunlit zone — Low / medium · no exploitation signal
impact 34.7 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
0.3%
0.3% → 0.4%
Last analysed / modified upstream
Versions of the package fastapi-sso before 0.19.0 are vulnerable to Cross-site Request Forgery (CSRF) due to the improper validation of the OAuth state parameter during the authentication callback. While the get_login_url method allows for state generation, it does not persist the state or bind it to the user's session. Consequently, the verify_and_process method accepts the state received in the query parameters without verifying it against a trusted local value. This allows a remote attacker to trick a victim into visiting a malicious callback URL, which can result in the attacker's account being linked to the victim's internal account.
fastapi-sso < 0.19.0Upgrade to a patched release:
fastapi-sso 0.19.0