Advisories

python-jose through 3.5.0 Algorithm Confusion via DER-encoded Public Key as HMAC Secret

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severity
critical
date
Affecting
  • python-jose <= 3.5.0

CWE
  • CWE-347 Improper Verification of Cryptographic Signature
CVSS
9.3
CVSS V4 Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Credit
George Chen
Description
python-jose through 3.5.0 fails to properly validate asymmetric keys in HMAC initialization, accepting DER-encoded public keys that lack PEM armor or SSH prefixes. Attackers holding the service's public key can forge HS256 tokens that pass verification when algorithms are not explicitly restricted. This is an incomplete fix for CVE-2024-33663.

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