CVE-2026-102946

joserfc: JWS signature verification bypass via empty signatures array in jws.deserialize_json

State
Published
Severity
9.1 Critical
Published
Oct 15, 2026
Updated
Oct 15, 2026
Reserved
Sep 29, 2026

Read the record on cve.org

Description

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.4, joserfc.jws.deserialize_json() accepts a JWS General JSON Serialization with an empty signatures array as authenticated. The verify_general_json() loop performs no iterations for the empty array and returns success because no signature check failed, allowing an attacker without a signing key to supply an arbitrary payload that relying applications may treat as authentic. The issue affects the General JSON Serialization path; compact JWS and JWT decoding, Flattened JSON serialization, and JWE JSON processing do not follow this vulnerable path. This issue is fixed in version 1.7.4.

Scores

CVSSScoreVectorSource
3.19.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NGitHub_M

Weaknesses

  • CWE-290 Authentication Bypass by Spoofing
  • CWE-345 Insufficient Verification of Data Authenticity
  • CWE-347 Improper Verification of Cryptographic Signature

Affected Products

ProductVersions
joserfcauthlib
  • < 1.7.4Affected

References

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