CVE-2013-4238: Canonical Ubuntu Linux

Medium severity, CVSS 4.3. EPSS: 5.3% chance of exploitation in the next 30 days.

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.

Affected products

• Canonical Ubuntu Linux: version 10.04 only
• Opensuse Opensuse: version 11.4 only; version 12.2 only; version 12.3 only
• Python Python: version 2.6.1 only; version 2.6.2 only; version 2.6.3 only; version 2.6.4 only; version 2.6.5 only; version 2.6.6 only; …

Published 2013-08-18. Last modified 2026-06-16.