CVE-2013-4314

Name of the Vulnerable Software and Affected Versions pyOpenSSL versions prior to 0.13.1

Description The issue arises from the improper handling of a 0 character in a domain name within the Subject Alternative Name field of an X.509 certificate by the X509Extension in pyOpenSSL. This allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.

Recommendations For pyOpenSSL versions prior to 0.13.1, update to version 0.13.1 or later to resolve the issue. As a temporary workaround, consider restricting the acceptance of certificates with domain names containing the 0 character in the Subject Alternative Name field.