CVE-2021-29921

    Dashboard / Vulnerabilities / CVE-2021-29921

    CVE-2021-29921

    Published: 6 May 2021Last Modified: 7 Aug 2026

    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://lists.debian.org/debian-lts-announce/2024/12/msg00000.html, https://www.oracle.com/security-alerts/cpujul2022.html, https://docs.python.org/3/library/ipaddress.html, https://github.com/python/cpython/blob/63298930fb531ba2bb4f23bc3b915dbf1e17e9e1/Misc/NEWS.d/3.8.0a4.rst, https://github.com/sickcodes, https://python-security.readthedocs.io/vuln/ipaddress-ipv4-leading-zeros.html, https://security.gentoo.org/glsa/202305-02, https://security.netapp.com/advisory/ntap-20210622-0003/, https://bugs.python.org/issue36384, https://github.com/python/cpython/pull/12577, https://github.com/python/cpython/pull/25099, https://www.oracle.com//security-alerts/cpujul2021.html, https://www.oracle.com/security-alerts/cpuapr2022.html, https://www.oracle.com/security-alerts/cpujan2022.html, https://www.oracle.com/security-alerts/cpuoct2021.html, https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-014.md, https://sick.codes/sick-2021-014

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- cf616f9f924f9e60b6158ff4aaed8306382b4c31
    Fixed -None

    Affected versions

    20.3.2

    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-2021-29921 | CVE-DB