CVE-2026-48526 PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed

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...

CVE-2026-48526

PyJWT (Python) prior to 2.13.0 did not validate the use of JSON Web Keys in HMAC verification, allowing an attacker to use the issuer public key as the HMAC secret during token verification. This could enable forging tokens when mixing RS/EC/JWK and HS algorithms. The issue is fixed in PyJWT 2.13...