CVE-2026-110826: AshAuthentication log_out_everywhere leaves sessions valid after a password reset or non-atomic password change

Summary

Improper Session Invalidation after Authentication Credential Change vulnerability in team-alembic ashauthentication allows an attacker holding a victim's session token to stay signed in after the victim resets or changes their password.

With applyonpasswordchange? true, AshAuthentication.AddOn.LogOutEverywhere.Transformer adds OnPasswordChange to update actions as a global change guarded by where: changing(hashedpassword). That condition is evaluated before the action's beforeaction hooks run, but AshAuthentication.Strategy.Password.HashPasswordChange sets the new hash in a beforeaction hook, so for every non-atomic password change the condition is false and the user's stored tokens are not revoked. The generated password reset action and the installer's changepassword action are both non-atomic.

This issue affects ashauthentication: from 4.5.0 before 4.15.1 and from 5.0.0-rc.0 before 5.0.0-rc.16.

Configurations

The logouteverywhere add-on sets applyonpasswordchange? true, as mix ashauthentication.install writes, and the password is changed through a non-atomic update action, which includes the generated password reset action and the installer's changepassword action. The attacker must already hold one of the victim's session tokens.