CVE-2026-48523 (GCVE-0-2026-48523)
Vulnerability from cvelistv5
Published
2026-05-28 15:10
Modified
2026-05-28 15:27
CWE
  • CWE-347 - Improper Verification of Cryptographic Signature
Summary
PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0.
Impacted products
Vendor Product Version
jpadilla pyjwt Version: >= 2.9.0, < 2.13.0
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Show details on NVD website


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