python-jose algorithm confusion guard bypassed by DER-encoded public keys

MEDIUM 6.5CVE-2024-33663 · CVE-2026-85394 · GHSA-3qf3-8w2g-rqmx · Published 26/04/2024 · updated 17/06/2026

In short

CVE-2024-33663 is a MEDIUM (CVSS 6.5) vulnerability affecting python-jose, python-jose (python-jose project).
Chance of exploitation in the next 30 days (EPSS): 0.31%, higher than 23.7% of all vulnerabilities.
Fix: update to 3.4.0 or later.

Package	Affected versions	Patched versions
python-jose PyPI	`≤ 3.5.0< 3.4.0`	`3.4.0`
python-jose python-jose_project	`≤ 3.3.0`	No fix yet

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.

NVD description

python-jose through 3.3.0 has algorithm confusion with OpenSSH ECDSA keys and other key formats. This is similar to CVE-2022-29217.