Improper Verification of Cryptographic Signature in jwcrypto - CVE-2026-84185
Published: September 2, 2026
Vulnerability identifier: #VU146777
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84185
CWE-ID: CWE-347
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to perform unauthorized actions.
The vulnerability exists due to improper verification of cryptographic signature in JWKSet verification in jwcrypto/jws.py when verifying a General JSON Serialization JWS with a supplied JWKSet. A remote privileged user can provide a crafted JWS signed with one trusted key while declaring a different kid header to perform unauthorized actions.
Exploitation requires that the attacker possess a valid signing key in the application\'s trusted JWKSet and that the consuming application rely on kid for an authorization decision.
Affected software
jwcrypto
How to mitigate CVE-2026-84185
Install security update from vendor's website.
jwcrypto - update to 1.6.0