PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, when the verifier is decoding JSON Web Tokens, while supporting both asymmetric and HMAC algorithms, the library does not validate use of JSON Web Keys in HMAC algorithm, allowing attacker to use the issuer public key as the secret key for HMAC algorithm. This vulnerability is fixed in 2.13.0.
History

Thu, 28 May 2026 15:30:00 +0000

Type Values Removed Values Added
Description PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, when the verifier is decoding JSON Web Tokens, while supporting both asymmetric and HMAC algorithms, the library does not validate use of JSON Web Keys in HMAC algorithm, allowing attacker to use the issuer public key as the secret key for HMAC algorithm. This vulnerability is fixed in 2.13.0.
Title PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed
Weaknesses CWE-287
CWE-347
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-28T15:09:09.258Z

Reserved: 2026-05-21T16:18:10.619Z

Link: CVE-2026-48526

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-28T16:16:29.657

Modified: 2026-05-28T16:16:29.657

Link: CVE-2026-48526

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.