Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

CVE-2026-117656

Gravedad CVSS v4.0:
CRÍTICA
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
31/10/2026
Última modificación:
06/11/2026

Descripción

*** Pendiente de traducción *** Acceptance of Extraneous Untrusted Data With Trusted Data vulnerability in the Sign in with Apple strategy in pow-auth Assent allows an unauthenticated remote attacker to impersonate another user via the user parameter of the authorization callback.<br /> <br /> Apple posts the user&amp;#39;s name to the callback endpoint in a user form parameter that the browser submits and the client controls. Assent.Strategy.Apple.callback/2 in lib/assent/strategies/apple.ex decodes that parameter, and fetch_user/2 merges it over the claims of the verified ID token, so the unverified map wins. An attacker who completes a Sign in with Apple login with their own Apple ID and edits the user parameter can replace sub, email, and any other claim. Applications that look up, link, or authorize accounts by the returned subject or email then act on the attacker&amp;#39;s values.<br /> <br /> This issue affects assent: from 0.1.25 before 0.3.2.