CVE-2026-75509

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.

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 4.2

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

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

Configurations

No configuration.

History

12 Oct 2026, 15:10

Type	Values Removed	Values Added
Summary		(es) joserfc es una biblioteca de Python que proporciona una implementación de varios estándares de Firma y Cifrado de Objetos JSON (JOSE). Antes de la versión 1.7.3, JWTClaimsRegistry aplica la coincidencia de membresía a las reclamaciones iss y sub con valores de lista, permitiendo que un iss con valor de matriz que contiene el emisor esperado pase una verificación de igualdad prevista y posibilitando la omisión de la validación del emisor. Este problema se corrige en la versión 1.7.3.

Information

Published : 2026-08-24 20:17

Updated : 2026-10-12 15:10

NVD link : CVE-2026-75509

Mitre link : CVE-2026-75509

CVE.ORG link : CVE-2026-75509

JSON object : View

Products Affected

No product.

CWE

CWE-290

Authentication Bypass by Spoofing

CWE-345

Insufficient Verification of Data Authenticity

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