SB2026092935 - Signature verification bypass in Authlib

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Main Vulnerability Database SB2026092935

SB2026092935 - Signature verification bypass in Authlib

Published: September 29, 2026 Updated: September 30, 2026

Security Bulletin ID SB2026092935
CSH Severity
High
Patch available
NO
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper verification of cryptographic signature (CVE-ID: CVE-2026-96760)

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to forge arbitrary authenticated payloads.

The vulnerability exists due to improper verification of cryptographic signatures in the Authlib JsonWebSignature.deserialize_json() function when processing JWS general JSON serialization objects. A remote attacker can submit a JWS object with an empty signatures array to forge arbitrary authenticated payloads.


Remediation

Cybersecurity Help is not aware of any official remediation provided by the vendor.

References