UBUNTU-CVE-2018-10903

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    UBUNTU-CVE-2018-10903

    Published: 20 Jul 2018Last Modified: 4 Feb 2026
    Upstream:
    CVE-2018-10903
    Aliases:
    USN-3720-1

    Summary:

    Details: A flaw was found in python-cryptography versions between >=1.9.0 and <2.3. The finalize_with_tag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalize_with_tag an attacker could craft an invalid payload with a shortened tag (e.g. 1 byte) such that they would have a 1 in 256 chance of passing the MAC check. GCM tag forgeries can cause key leakage.

    References: https://ubuntu.com/security/CVE-2018-10903, https://ubuntu.com/security/notices/USN-3720-1, https://www.cve.org/CVERecord?id=CVE-2018-10903

    Affected packages

    Package

    Name: python-cryptography

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

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -2.1.4-1ubuntu1.2

    Affected versions

    1.9-1

    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