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Critical · 9.1 CVE-2026-86533 EEF-CVE-2026-86533EUVD-2026-81486GHSA-m6x4-4gvp-xwjr

Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix

Published Sep 17, 2026 · Updated Sep 17, 2026 · Assigned by EEF

Description

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.

Affected products

VendorProductAffectedFixed
team-alembic ash_authentication 4.9.1 – < 4.15.0, 5.0.0-rc.0 – < 5.0.0-rc.14 4.15.0
team-alembic ash_authentication_phoenix 2.10.0 – < 2.17.4, 3.0.0-rc.0 – < 3.0.0-rc.11 2.17.4

Affected packages

EcosystemPackageAffectedFixedRecord
Hex ash_authentication >= 4.9.1, < 4.15.0 · >= 5.0.0-rc.0, < 5.0.0-rc.14 4.15.0, 5.0.0-rc.14 EEF-CVE-2026-86533
Hex ash_authentication_phoenix >= 2.10.0, < 2.17.4 · >= 3.0.0-rc.0, < 3.0.0-rc.11 2.17.4, 3.0.0-rc.11 EEF-CVE-2026-86533

References