{"id":"PYSEC-2026-665","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.","aliases":["CVE-2010-4237","GHSA-7gf7-7wx4-mxmw"],"modified":"2026-07-06T08:00:38.849597485Z","published":"2026-07-02T14:13:17.606556Z","references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2010-4237"},{"type":"WEB","url":"https://github.com/dscho/hg/commit/4ea63fb25ceeeaaa4cd1026f733b7ea7672c30b3"},{"type":"WEB","url":"https://github.com/dscho/hg/commit/89baabf4fb7abf30ef6fdcf3d455a7893e5cc145"},{"type":"WEB","url":"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=598841"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2010-4237"},{"type":"WEB","url":"https://bz.mercurial-scm.org/show_bug.cgi?id=2407"},{"type":"WEB","url":"https://repo.mercurial-scm.org/hg/rev/6ab4a7d3c179"},{"type":"WEB","url":"https://repo.mercurial-scm.org/hg/rev/f2937d6492c5"},{"type":"WEB","url":"https://security-tracker.debian.org/tracker/CVE-2010-4237"},{"type":"PACKAGE","url":"https://pypi.org/project/mercurial"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-7gf7-7wx4-mxmw"}],"affected":[{"package":{"name":"mercurial","ecosystem":"PyPI","purl":"pkg:pypi/mercurial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.4"}]}],"versions":["0.8.1","0.9","0.9.1","0.9.2","0.9.3","0.9.4","0.9.5","1.0","1.0.1","1.0.2","1.1","1.1.1","1.1.2","1.2","1.2.1","1.3","1.3.1","1.4","1.4.1","1.4.2","1.4.3","1.5","1.5.1","1.5.2","1.5.3","1.5.4","1.6","1.6.1","1.6.2","1.6.3"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/mercurial/PYSEC-2026-665.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}