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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-102946
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-15 19:17:13 UTC
Updated2026-10-15 20:17:05 UTC
Descriptionjoserfc 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.

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Problem Types: CWE-290 | CWE-345 | CWE-347 | CWE-290 CWE-290: Authentication Bypass by Spoofing | CWE-345 CWE-345: Insufficient Verification of Data Authenticity | CWE-347 CWE-347: Improper Verification of Cryptographic Signature

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNADECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Authlib Joserfc affected < 1.7.4 Not specified

References

ReferenceSourceLinkTags
github.com/authlib/joserfc/security/advisories/GHSA-4pp3-559j-c5c2 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/authlib/joserfc/releases/tag/1.7.4 [email protected] github.com
github.com/authlib/joserfc/commit/f409f8f058225d7686acab6546c94593e4c1bfbe [email protected] github.com
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