PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.4epss 0.4%
exploitation probability
0.4%top 68% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected products
jpadilla · pyjwtReferences
https://access.redhat.com/errata/RHSA-2026:25902https://access.redhat.com/errata/RHSA-2026:25928https://access.redhat.com/errata/RHSA-2026:26206https://access.redhat.com/errata/RHSA-2026:28571https://access.redhat.com/errata/RHSA-2026:30076https://access.redhat.com/errata/RHSA-2026:30088https://access.redhat.com/errata/RHSA-2026:30089https://access.redhat.com/errata/RHSA-2026:33683https://access.redhat.com/errata/RHSA-2026:34160https://access.redhat.com/errata/RHSA-2026:34365https://access.redhat.com/errata/RHSA-2026:34374https://access.redhat.com/errata/RHSA-2026:35835