CVE-2021-28363

    Dashboard / Vulnerabilities / CVE-2021-28363

    CVE-2021-28363

    Published: 15 Mar 2021Last Modified: 7 Aug 2026

    Summary:

    Details: The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. The initial connection to the HTTPS proxy (if an SSLContext isn't given via proxy_config) doesn't verify the hostname of the certificate. This means certificates for different servers that still validate properly with the default urllib3 SSLContext will be silently accepted.

    References: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S65ZQVZ2ODGB52IC7VJDBUK4M5INCXL/, https://github.com/urllib3/urllib3/security/advisories/GHSA-5phf-pp7p-vc2r, https://pypi.org/project/urllib3/1.26.4/, https://security.gentoo.org/glsa/202107-36, https://security.gentoo.org/glsa/202305-02, https://security.netapp.com/advisory/ntap-20240621-0007/, https://github.com/urllib3/urllib3/commit/8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0, https://github.com/urllib3/urllib3/commits/main, https://www.oracle.com/security-alerts/cpuoct2021.html

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- ddb8c96bd93f3a00fe9eba142e6739533c2b7164
    Fixed -a8913042b676c510e94fc2b097f6b514ae11a537

    Affected versions

    1.26.3
    1.26.2
    1.26.1
    1.26.0

    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-2021-28363 | CVE-DB