UBUNTU-CVE-2017-11424

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    UBUNTU-CVE-2017-11424

    Published: 24 Aug 2017Last Modified: 4 Feb 2026
    Upstream:
    CVE-2017-11424
    Aliases:
    USN-3407-1

    Summary:

    Details: In PyJWT 1.5.0 and below the `invalid_strings` check in `HMACAlgorithm.prepare_key` does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string `-----BEGIN RSA PUBLIC KEY-----` which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.

    References: https://ubuntu.com/security/CVE-2017-11424, https://ubuntu.com/security/notices/USN-3407-1, https://www.cve.org/CVERecord?id=CVE-2017-11424

    Affected packages

    Package

    Name: pyjwt

    Purl: pkg:deb/ubuntu/[email protected]?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1.3.0-1ubuntu0.1

    Affected versions

    1.0.0-0ubuntu1

    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