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.
https://mail.python.org/pipermail/pyopenssl-users/2013-September/000478.html
https://bugzilla.redhat.com/show_bug.cgi?id=1005325
http://www.ubuntu.com/usn/USN-1965-1
http://www.openwall.com/lists/oss-security/2013/09/06/2
http://www.debian.org/security/2013/dsa-2763
http://lists.opensuse.org/opensuse-updates/2013-11/msg00015.html
Published: 2013-09-30
Updated: 2025-04-11
Base Score: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
Base Score: 8.7
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: High