Description
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.
Published: 2025-12-19
Score: 6.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-hp6r-r9vc-q8wx FastAPI SSP is vulnerable to Cross-site Request Forgery (CSRF) through improper OAuth parameter validation
History

Sun, 21 Dec 2025 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Tomasvotava
Tomasvotava fastapi-sso
Vendors & Products Tomasvotava
Tomasvotava fastapi-sso

Fri, 19 Dec 2025 16:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 19 Dec 2025 05:15:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-285
References
Metrics cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N/E:P'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:P'}


Subscriptions

Tomasvotava Fastapi-sso
cve-icon MITRE

Status: PUBLISHED

Assigner: snyk

Published:

Updated: 2025-12-19T15:39:15.674Z

Reserved: 2025-12-11T17:14:20.112Z

Link: CVE-2025-14546

cve-icon Vulnrichment

Updated: 2025-12-19T15:39:11.495Z

cve-icon NVD

Status : Deferred

Published: 2025-12-19T05:16:09.497

Modified: 2026-04-29T01:00:01.613

Link: CVE-2025-14546

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2025-12-21T21:14:54Z

Weaknesses