CVE-2026-81632: Single-use sign-in token placed in a redirect query string in AshAuthenticationPhoenix

Severity: high (CVSS 7.2 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-09-18
Weakness: CWE-598

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.

Affected products

team-alembic ash_authentication: from 3.10.5 before 4.15.0; from 5.0.0-rc.0 before 5.0.0-rc.14 — fixed in 4.15.0, 5.0.0-rc.14
team-alembic ash_authentication_phoenix: from 1.7.0 before 2.17.4; from 3.0.0-rc.0 before 3.0.0-rc.11 — fixed in 2.17.4, 3.0.0-rc.11

How to fix

Upgrade to a fixed version: team-alembic ash_authentication 4.15.0, 5.0.0-rc.14; team-alembic ash_authentication_phoenix 2.17.4, 3.0.0-rc.11. Check the vendor advisory for mitigations.

References

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