CVE-2026-75509joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)

Descripción

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.

Datos: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Se publican tal como los indican las fuentes, en inglés.

Productos y versiones afectados

Referencias y parches

• https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj
• https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1