CVE-2026-75509 (GCVE-0-2026-75509)

Vulnerability from cvelistv5 – Published: 2026-08-24 20:08 – Updated: 2026-08-25 16:42
VLAI
Title
joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)
Summary
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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-25 16:38 UTC
CWE
  • CWE-290 - Authentication Bypass by Spoofing
  • CWE-345 - Insufficient Verification of Data Authenticity
Assigner
References
Impacted products
Vendor Product Version CPE status
authlib joserfc Affected: < 1.7.3
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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