{"affected":[{"package":{"ecosystem":"Hex","name":"ash_authentication","purl":"pkg:hex/ash_authentication"},"ranges":[{"events":[{"introduced":"0.6.0"},{"fixed":"4.15.0"}],"type":"SEMVER"},{"events":[{"introduced":"5.0.0-rc.0"},{"fixed":"5.0.0-rc.14"}],"type":"SEMVER"}],"versions":["3.0.3","3.1.0","3.2.0","3.2.1","3.2.2","3.3.0","3.3.1","3.5.0","3.5.1","3.5.2","3.5.3","3.6.0","3.6.1","3.7.0","3.7.1","3.7.2","3.7.3","3.7.4","3.7.5","3.7.6","3.7.8","3.7.9","3.8.0","3.9.0","3.9.1","3.9.2","3.9.3","3.9.4","3.9.5","3.9.6","3.10.0","3.10.1","3.10.2","3.10.3","3.10.4","3.10.5","3.10.6","3.10.7","3.10.8","3.11.0","3.11.1","3.11.2","3.11.3","3.11.4","3.11.5","3.11.6","3.11.7","3.11.8","3.11.9","3.11.10","3.11.11","3.11.12","3.11.13","3.11.14","3.11.15","3.11.16","3.12.0","3.12.1","3.12.2","3.12.3","3.12.4","4.0.0-rc.0","4.0.0-rc.1","4.0.0-rc.2","4.0.0-rc.3","4.0.0-rc.5","4.0.0-rc.6","4.0.0","4.0.1","4.0.2","4.0.3","4.0.4","4.1.0","4.2.0","4.2.1","4.2.2","4.2.3","4.2.4","4.2.5","4.2.6","4.2.7","4.3.0","4.3.1","4.3.2","4.3.3","4.3.4","4.3.5","4.3.6","4.3.7","4.3.8","4.3.9","4.3.10","4.3.11","4.3.12","4.4.0","4.4.1","4.4.2","4.4.3","4.4.4","4.4.5","4.4.6","4.4.7","4.4.8","4.4.9","4.5.0","4.5.1","4.5.2","4.5.3","4.5.4","4.5.5","4.5.6","4.6.0","4.6.1","4.6.2","4.6.3","4.6.4","4.7.0","4.7.1","4.7.2","4.7.3","4.7.4","4.7.5","4.7.6","4.8.0","4.8.1","4.8.2","4.8.3","4.8.5","4.8.6","4.8.7","4.9.0","4.9.1","4.9.2","4.9.3","4.9.4","4.9.5","4.9.6","4.9.7","4.9.8","4.9.9","4.10.0","4.11.0","4.12.0","4.13.0","4.13.1","4.13.2","4.13.3","4.13.4","4.13.5","4.13.6","4.13.7","4.14.0","4.14.1","4.14.2","5.0.0-rc.0","5.0.0-rc.1","5.0.0-rc.2","5.0.0-rc.3","5.0.0-rc.4","5.0.0-rc.5","5.0.0-rc.6","5.0.0-rc.7","5.0.0-rc.8","5.0.0-rc.9","5.0.0-rc.10","5.0.0-rc.11","5.0.0-rc.12","5.0.0-rc.13"]},{"ranges":[{"events":[{"introduced":"c5f589058e04239263f50a1430eb17ea6d5dd1a2"},{"fixed":"bd4352303bc9d72d007f6818775267585a4bcc2f"},{"fixed":"d7f939cd02bd618bcaa304631846fa75ffc419d7"}],"repo":"https://github.com/team-alembic/ash_authentication","type":"GIT"}]}],"aliases":["GHSA-3vcj-gxx8-3p44","CVE-2026-81637"],"credits":[{"name":"Peter Ullrich","type":"REPORTER"},{"name":"Jonatan Männchen / EEF","type":"ANALYST"},{"name":"James Harton","type":"REMEDIATION_DEVELOPER"}],"database_specific":{"capec_ids":["CAPEC-60"],"cpe_ids":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-613"]},"details":"## Summary\n\nInsufficient Session Expiration vulnerability in team-alembic AshAuthentication allows an attacker who obtains a victim's OAuth2 `state` value to replay the callback and sign that victim into an attacker-controlled account.\n\n`AshAuthentication.Strategy.OAuth2.Plug.callback/2` clears the stored `session_params` through a rebinding step inside its `with` chain, `conn <- delete_session(conn, session_key)`. Elixir evaluates the `else` block in the scope enclosing the `with`, so every failure path (the provider returning `?error=access_denied`, an invalid code, a token-exchange error, or a registration or sign-in failure) reaches `store_authentication_result/2` holding the original connection and the session entry is never removed. The value the module's own comment describes as protection against a CSRF-related attack is therefore consumed only when authentication succeeds, and survives a cancelled or failed attempt until the next request phase or session expiry.\n\nThis issue affects ash_authentication: from 0.6.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.","id":"EEF-CVE-2026-81637","modified":"2026-09-17T13:09:07.408695Z","published":"2026-09-17T13:09:06.571Z","references":[{"type":"ADVISORY","url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-3vcj-gxx8-3p44"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-81637.html"},{"type":"WEB","url":"https://github.com/team-alembic/ash_authentication/commit/c5f589058e04239263f50a1430eb17ea6d5dd1a2"},{"type":"FIX","url":"https://github.com/team-alembic/ash_authentication/commit/bd4352303bc9d72d007f6818775267585a4bcc2f"},{"type":"FIX","url":"https://github.com/team-alembic/ash_authentication/commit/d7f939cd02bd618bcaa304631846fa75ffc419d7"},{"type":"PACKAGE","url":"https://hex.pm/packages/ash_authentication"}],"related":[],"schema_version":"1.7.3","severity":[{"score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","type":"CVSS_V4"}],"summary":"Replayable OAuth2 CSRF state retained after a failed callback in AshAuthentication","upstream":[]}