Insufficient Session Expiration vulnerability in team-alembic AshAuthentication and AshAuthentication Phoenix allows a revoked session to remain fully authenticated. A resource configured with session_identifier :jti and require_token_presence_for_authentication? disabled stores its session value as <jti>:<subject>. The jti is there so that signing out can revoke that one session. Neither reader consults it: AshAuthentication.Plug.Helpers.authenticate_resource_from_session/4 and AshAuthentication.Phoenix.LiveSession.on_mount/4 both split the value with split_identifier/2, discard the jti and pass the bare subject to AshAuthentication.subject_to_user/3, which reloads the record. The token-presence branch of each function does check its token, calling AshAuthentication.TokenResource.Actions.get_token/3 with the jti and the purpose user. Because the revocation record is never read, neither its revoked state nor its expiry constrains the session, so a session captured before sign-out keeps working. This issue affects ash_authentication: from 4.9.1 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14; ash_authentication_phoenix: from 2.10.0 before 2.17.4 and from 3.0.0-rc.0 before 3.0.0-rc.11.
https://github.com/team-alembic/ash_authentication_phoenix/security/advisories/GHSA-m6x4-4gvp-xwjr
https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-w374-hvrx-66hg
https://osv.dev/vulnerability/EEF-CVE-2026-86533
https://github.com/team-alembic/ash_authentication/commit/fcaeb73f76f8f2e9aef8bf637690d2a20dd97596
https://github.com/team-alembic/ash_authentication/commit/e28e911caa9728d76329afdb0fb26742ffe4eeef
https://github.com/team-alembic/ash_authentication/commit/a3f49f758f013d2ff086dd9c5ef2d94e921711b4
Published: 2026-09-17
Updated: 2026-09-18
Base Score: 5.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 8.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Severity: High
Base Score: 9.1
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: Critical
EPSS: 0.00647