UBUNTU-CVE-2021-29921

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    UBUNTU-CVE-2021-29921

    Published: 6 May 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-29921

    Summary:

    Details: In Python before 3,9,5, the ipaddress library mishandles leading zero characters in the octets of an IP address string. This (in some situations) allows attackers to bypass access control that is based on IP addresses.

    References: https://ubuntu.com/security/CVE-2021-29921, https://github.com/python/cpython/pull/25099, https://sick.codes/sick-2021-014, https://python-security.readthedocs.io/vuln/ipaddress-ipv4-leading-zeros.html, https://github.com/sickcodes, https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-014.md, https://github.com/python/cpython/pull/12577, https://docs.python.org/3/library/ipaddress.html, https://github.com/python/cpython/blob/63298930fb531ba2bb4f23bc3b915dbf1e17e9e1/Misc/NEWS.d/3.8.0a4.rst, https://ubuntu.com/security/notices/USN-4973-1, https://ubuntu.com/security/notices/USN-4973-2, https://www.cve.org/CVERecord?id=CVE-2021-29921, https://ubuntu.com/security/notices/USN-6891-1

    Affected packages

    Package

    Name: python3.8

    Purl: pkg:deb/ubuntu/[email protected]~18.04.2+esm2?arch=source&distro=esm-apps/bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -3.8.0-3ubuntu1~18.04.2+esm2

    Affected versions

    3.8.0-3~18.04
    3.8.0-3~18.04.1
    3.8.0-3ubuntu1~18.04.2
    3.8.0-3ubuntu1~18.04.2+esm1

    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
    UBUNTU-CVE-2021-29921 | CVE-DB