team-alembic ash_authentication up to 4.14.0/5.0.0-rc.13 OAuth2 Strategy AshAuthentication.Strategy.OAuth2.Plug.callback session expiration

Summaryinfo

A vulnerability labeled as critical has been found in team-alembic ash_authentication up to 4.14.0/5.0.0-rc.13. The impacted element is the function AshAuthentication.Strategy.OAuth2.Plug.callback of the component OAuth2 Strategy. Executing a manipulation can lead to session expiration. This vulnerability is tracked as CVE-2026-81637. The attack can be launched remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in team-alembic ash_authentication up to 4.14.0/5.0.0-rc.13. It has been declared as critical. This vulnerability affects the function AshAuthentication.Strategy.OAuth2.Plug.callback of the component OAuth2 Strategy. The manipulation with an unknown input leads to a session expiration vulnerability. The CWE definition for the vulnerability is CWE-613. According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization." As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-81637 since 09/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 4.15.0 or 5.0.0-rc.14 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• team-alembic

Name

• ash_authentication

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14.0
• 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

Website

• Product: https://github.com/team-alembic/ash_authentication/

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