CVE-2025-68481

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-12-19 21:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-13 11:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 5.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-12-19 21:15 UTC

Last modified

2026-10-13 11:10 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-285

Record status

Analyzed

Affected

• fastapi-users Project Fastapi Users < 15.0.2

Attack profile CVSS 3.1 · 5.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-68481.md and follow it. Check whether this project is affected by CVE-2025-68481. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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