CVE-2026-85394

    Dashboard / Vulnerabilities / CVE-2026-85394

    CVE-2026-85394

    Published: 3 Sept 2026Last Modified: 26 Sept 2026

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

    Details: 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.

    References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/85xxx/CVE-2026-85394.json, https://github.com/advisories/GHSA-6c5p-j8vq-pqhj, https://nvd.nist.gov/vuln/detail/CVE-2026-85394, https://www.vulncheck.com/advisories/python-jose-through-3.5.0-algorithm-confusion-via-der-encoded-public-key-as-hmac-secret, 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

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -018b310ddb8b50dcfd09a0c152117835a21dd656

    Affected versions

    3.4.0

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2026-85394 | CVE-DB