EUVD Vulnerability Catalog
EUVD-2026-70671
Severity: CRITICAL
Base Score: 9.3
CVSS Version: 4.0
Vulnerability 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.
CVSS Vector Analysis
Below is the complete, human-readable breakdown of the CVSS metric string: 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
▪
Attack Vector (AV): Network
▪
Attack Complexity (AC): Low
▪
Attack Requirements (AT): None
▪
Privileges Required (PR): None
▪
User Interaction (UI): None
▪
Vulnerability Confidentiality Impact (VC): High
▪
Vulnerability Integrity Impact (VI): High
▪
Vulnerability Availability Impact (VA): None
▪
Subsequent Confidentiality Impact (SC): None
▪
Subsequent Integrity Impact (SI): None
▪
Subsequent Availability Impact (SA): None
Affected Vendors & Systems
Vendor
mpdavis
References & Advisory Links
- https://github.com/mpdavis/python-jose/issues/414
- https://github.com/mpdavis/python-jose
- https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/backends/native.py
- https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/utils.py
- https://github.com/advisories/GHSA-6c5p-j8vq-pqhj
- https://www.vulncheck.com/advisories/python-jose-through-3.5.0-algorithm-confusion-via-der-encoded-public-key-as-hmac-secret
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
VulnCheck
EPSS Probability
0
Known Aliases
CVE-2026-85394
Published On
2026-09-03
Last Updated
2026-09-03