CVE-2026-81632 Single-use sign-in token placed in a redirect query string in AshAuthenticationPhoenix
Attackers with log access can steal sign-in tokens exposed in redirect URLs, allowing them to authenticate as the victim.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-81632?
CVE-2026-81632 is a high-severity vulnerability in team-alembic ash_authentication, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Use of HTTP Request With Sensitive Query String vulnerability in team-alembic AshAuthenticationPhoenix allows someone able to read access logs, proxy logs or browser history to recover a single-use sign-in token and authenticate as its owner.
After a successful password sign-in, AshAuthentication.Phoenix.Components.Password.SignInForm builds the sign_in_with_token path with the freshly issued user.__metadata__.token as a query parameter and redirects the browser to it with a GET. The token therefore travels in the request line, where web servers, reverse proxies, request telemetry and the browser's own history record it, all of which outlive the request and are ordinarily less protected than session storage. The redirect destination is restricted to a local path, so this is not an open redirect; the exposure is the retention of a live credential.
This issue affects ash_authentication_phoenix: from 1.7.0 before 2.17.4 and from 3.0.0-rc.0 before 3.0.0-rc.11; ash_authentication: from 3.10.5 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
Weakness: CWE-598
Which versions are affected by CVE-2026-81632?
2 open source packages ship an affected version, including ash_authentication and ash_authentication_phoenix.
| Package | Affected | Fixed in |
|---|---|---|
ash_authentication Hex | From 3.10.5 | 4.15.0, 5.0.0-rc.14 |
ash_authentication_phoenix Hex | From 1.7.0 | 2.17.4, 3.0.0-rc.11 |
How do I fix CVE-2026-81632?
Upgrade ash_authentication to a fixed version for your release line: 4.15.0 or 5.0.0-rc.14.
Is CVE-2026-81632 being exploited?
There is no known exploitation of CVE-2026-81632 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-81632, GHSA-8jh5-339h-mqx9.