{"cve":"CVE-2013-4238","nvd":{"published":"2013-08-18T02:52:22.943","modified":"2026-06-16T23:56:52.227","status":"Modified","description":"The ssl.match_hostname function in the SSL module in Python 2.6 through 3.4 does not properly handle a '\\0' character in a domain name in the Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.","cvss_v4":null,"cvss_v3":null,"cwes":["CWE-20"],"references":["http://bugs.python.org/issue18709","http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html","http://lists.opensuse.org/opensuse-updates/2013-09/msg00026.html","http://lists.opensuse.org/opensuse-updates/2013-09/msg00027.html","http://lists.opensuse.org/opensuse-updates/2013-09/msg00028.html"],"products":["canonical:ubuntu_linux","opensuse:opensuse","python:python"],"source":"nvd","synced_at":"2026-10-19T20:29:16.037019470+00:00"},"epss":{"cve":"CVE-2013-4238","score":0.05347,"percentile":0.92633,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}