EEF-CVE-2026-119215

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EEF-CVE-2026-119215

Summary: AshAuthentication TOTP setup lets a user install their own authenticator secret on another user's account

Details: ## Summary Authorization Bypass Through User-Controlled Key vulnerability in team-alembic ash_authentication allows a user with an account to install a TOTP secret they control on another user's account, and then sign in as that user or hold their second factor. `AshAuthentication.Strategy.Totp.ConfirmSetupChange` verified a setup token but did not check that it was issued to the record being confirmed, so an attacker's own pending secret could be confirmed onto another user's record. The TOTP setup changes, `ConfirmSetupChange`, `GeneratePendingSetupChange` and `GenerateSecretChange`, also marked their changesets as AshAuthentication interactions, which the standard `AshAuthenticationInteraction` policy bypass lets through. A policy limiting `setup` and `confirm_setup` to the actor's own record therefore never ran when an application exposed those actions by record key, and a direct `setup` call on another user's record returned that user's pending secret and setup token. This issue affects ash_authentication: from 5.0.0-rc.0 before 5.0.0-rc.16. ## Workarounds Do not expose `setup` or `confirm_setup` on a record the caller chooses. Call them through `AshAuthentication.Strategy.Totp.Actions` with the signed-in user, as the built-in routes do. ## Configurations An application exposes the TOTP `setup` or `confirm_setup` action on a record the caller identifies, for example through AshJsonApi, AshGraphql or a controller that passes a looked-up user to `AshAuthentication.Strategy.Totp.Actions.confirm_setup/3`, and the attacker can read the victim's user record. Installing the attacker's secret requires `confirm_setup_enabled? true`; signing in with it alone requires `sign_in_enabled? true`. The routes AshAuthentication and AshAuthenticationPhoenix provide always use the signed-in user and are not affected.

References: https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-gx67-694c-655c, https://cna.erlef.org/cves/CVE-2026-119215.html, https://github.com/team-alembic/ash_authentication/commit/6e7a880698614887527a87df206b4eb0c0fbd8c1, https://github.com/team-alembic/ash_authentication/commit/4058be0f519c2e9b0d2266e90f9c7d8547d54574, https://hex.pm/packages/ash_authentication