CVE-2026-81637: fallo de gravedad baja en team-alembic ash_authentication
Replayable OAuth2 CSRF state retained after a failed callback in AshAuthentication
Publicada el
Aviso por correo cuando entre en el KEV, tenga PoC pública o suba de nota.
8Vexday Risk Score
Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.
ssvc Trackcvss 2.3epss 0.6%
Insufficient 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.
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.
This 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.
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
Productos afectados
team-alembic · ash_authenticationCVEs relacionadas — team-alembic ash_authentication
En el mismo producto, de las más peligrosas a las menos.
CVE-2026-86533CRITICALRevoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication PhoenixEPSS 0.9%CVE-2026-76949CRITICALRemember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacementEPSS 0.8%CVE-2026-85500CRITICAL`require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthenticationEPSS 0.8%CVE-2026-66882LOWReflected XSS in AshAuthentication confirmation and magic link interaction formsEPSS 0.8%CVE-2026-88952CRITICALOAuth2 sign-in attached to an existing account without an email comparison in AshAuthenticationEPSS 0.7%CVE-2026-86688HIGHSession id is not renewed on authentication in ash_authentication, allowing session fixationEPSS 0.7%
Referencias
https://cna.erlef.org/cves/CVE-2026-81637.htmlhttps://github.com/team-alembic/ash_authentication/commit/bd4352303bc9d72d007f6818775267585a4bcc2fhttps://github.com/team-alembic/ash_authentication/commit/c5f589058e04239263f50a1430eb17ea6d5dd1a2https://github.com/team-alembic/ash_authentication/commit/d7f939cd02bd618bcaa304631846fa75ffc419d7https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-3vcj-gxx8-3p44https://osv.dev/vulnerability/EEF-CVE-2026-81637