PYSEC-2026-665

    Dashboard / Vulnerabilities / PYSEC-2026-665

    PYSEC-2026-665

    Published: 2 Jul 2026Last Modified: 6 Jul 2026

    Summary: Mercurial Improper Certificate Validation vulnerability

    Details: Mercurial before 1.6.4 fails to verify the Common Name field of SSL certificates which allows remote attackers who acquire a certificate signed by a Certificate Authority to perform a man-in-the-middle attack.

    References: https://nvd.nist.gov/vuln/detail/CVE-2010-4237, https://github.com/dscho/hg/commit/4ea63fb25ceeeaaa4cd1026f733b7ea7672c30b3, https://github.com/dscho/hg/commit/89baabf4fb7abf30ef6fdcf3d455a7893e5cc145, https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=598841, https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2010-4237, https://bz.mercurial-scm.org/show_bug.cgi?id=2407, https://repo.mercurial-scm.org/hg/rev/6ab4a7d3c179, https://repo.mercurial-scm.org/hg/rev/f2937d6492c5, https://security-tracker.debian.org/tracker/CVE-2010-4237, https://pypi.org/project/mercurial, https://github.com/advisories/GHSA-7gf7-7wx4-mxmw

    Affected packages

    Package

    Name: mercurial

    Purl: pkg:pypi/mercurial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1.6.4

    Affected versions

    0.8.1

    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