CVE-2026-102268
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.
Published:Sep 28, 2026
Last Modified:Oct 7, 2026
EPS:Sep 28, 2026
EPSS Score:0.00196
CVSS Score:9.1
Affected Products
Vendor
Product
Action
Vendor
Jpadilla
Product
Pyjwt
Jpadilla
Pyjwt
Vendor
Pyjwt Project
Product
Pyjwt
Pyjwt Project
Pyjwt
Exploits
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Related CVEs
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
