Login CSRF via unbound OAuth state token
Published Dec 19, 2025 · Updated Dec 19, 2025
Login CSRF in FastAPI Users before 15.0.2 allows remote attackers to hijack OAuth callbacks by sending victims crafted callback URLs. The OAuth router generates state JWTs from an empty state_data dictionary and validates only their signature and expiry, without binding them to the initiating browser. Victim interaction is required; applications that link an authenticated user's account during callback expose permanent attacker-controlled SSO association, while other integrations log the victim into the attacker's account.
Summary
What happened
Login CSRF in FastAPI Users before 15.0.2 allows remote attackers to hijack OAuth callbacks by sending victims crafted callback URLs. The OAuth router generates state JWTs from an empty state_data dictionary and validates only their signature and expiry, without binding them to the initiating browser. Victim interaction is required; applications that link an authenticated user's account during callback expose permanent attacker-controlled SSO association, while other integrations log the victim into the attacker's account.
The record
- CVE
- CVE-2025-68481
- Published
- Dec 19, 2025
- Updated
- Dec 19, 2025
- Vendor
- FastAPI Users
- Product
- FastAPI Users
- Classifications
- CWE-352, CWE-285, T1566.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 19, 2025CVE publishedPublication date reported by the CVE source.
- Dec 19, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 15.0.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub advisory OAuth callback proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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