{"id":"CVE-2013-4314","aliases":["GHSA-6748-36qp-fx6r","PYSEC-2013-31"],"url":"https://o3.security/vulnerability/CVE-2013-4314","summary":"PyOpenSSL Mishandles NUL Byte In Certificate Subject Alternative Name","details":"The X509Extension in pyOpenSSL before 0.13.1 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.","published":"2013-09-30T21:55:09Z","modified":"2026-08-07T10:11:59.110036834Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"pyopenssl","fixedVersion":"0.13.1"}],"fix":{"url":"https://github.com/pyca/pyopenssl/commit/6bbf44a00b35fb28df1f66aa194b2fe95eab1ab2","label":"pyca/pyopenssl@6bbf44a"},"references":[{"type":"ADVISORY","url":"http://www.debian.org/security/2013/dsa-2763"},{"type":"ADVISORY","url":"http://www.ubuntu.com/usn/USN-1965-1"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=1005325"},{"type":"WEB","url":"http://lists.opensuse.org/opensuse-updates/2013-11/msg00015.html"},{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2013/09/06/2"},{"type":"WEB","url":"https://mail.python.org/pipermail/pyopenssl-users/2013-September/000478.html"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2013-4314"},{"type":"WEB","url":"https://github.com/pyca/pyopenssl/commit/6bbf44a00b35fb28df1f66aa194b2fe95eab1ab2"},{"type":"PACKAGE","url":"https://github.com/pyca/pyopenssl"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/pyopenssl/PYSEC-2013-31.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T10:11:59.110036834Z"}}