CVE-2026-48526
PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-287 CWE-347 |
| Vendor | jpadilla |
| Product | pyjwt |
| Published | May 28, 2026 |
| Last Updated | May 29, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
jpadilla / pyjwt
< 2.13.0