CVE-2025-68481
FastAPI Users Vulnerable to 1-click Account Takeover in Apps Using FastAPI SSO
Description
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 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.
INFO
Published Date :
Dec. 19, 2025, 9:15 p.m.
Last Modified :
Dec. 19, 2025, 9:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2025-68481
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update FastAPI Users to version 15.0.2 or later.
- Ensure state tokens are properly validated.
- Implement server-side session correlation.
- Add state data to tokens.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-68481.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-68481 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-68481
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-68481 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-68481 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Dec. 19, 2025
Action Type Old Value New Value Added Description 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 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N Added CWE CWE-352 Added CWE CWE-285 Added Reference https://github.com/fastapi-users/fastapi-users/blob/bcee8c9b884de31decb5d799aead3974a0b5b158/fastapi_users/router/oauth.py#L111 Added Reference https://github.com/fastapi-users/fastapi-users/blob/bcee8c9b884de31decb5d799aead3974a0b5b158/fastapi_users/router/oauth.py#L57 Added Reference https://github.com/fastapi-users/fastapi-users/commit/7cf413cd766b9cb0ab323ce424ddab2c0d235932 Added Reference https://github.com/fastapi-users/fastapi-users/security/advisories/GHSA-5j53-63w8-8625