AUGUST 4, 2026
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Case File

CVE-2026-27962

CRITICAL · CVSS 9.1 EPSS 0.55% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-03-16 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.1. Public exploit code or proof-of-concept references have been detected in its references. Exploitation may require the attacker to be authenticated.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-27962
Severity
CRITICAL
CVSS
9.1
EPSS
0.55%

Original NVD Description

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a JWK Header Injection vulnerability in authlib's JWS implementation allows an unauthenticated attacker to forge arbitrary JWT tokens that pass signature verification. When key=None is passed to any JWS deserialization function, the library extracts and uses the cryptographic key embedded in the attacker-controlled JWT jwk header field. An attacker can sign a token with their own private key, embed the matching public key in the header, and have the server accept the forged token as cryptographically valid — bypassing authentication and authorization entirely. This issue has been patched in version 1.6.9.

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