CVE-2013-4238

Severity: medium (CVSS 4.3 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2013-08-18 · updated 2026-06-16
Weakness: CWE-20

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.

Affected products

Canonical Ubuntu Linux: 10.04
Opensuse: 11.4, 12.2, 12.3
Python: 2.6.1, 2.6.2, 2.6.3, 2.6.4, 2.6.5, 2.6.6 (+26)

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
http://lists.opensuse.org/opensuse-updates/2013-09/msg00029.html
http://lists.opensuse.org/opensuse-updates/2013-09/msg00042.html
http://lists.opensuse.org/opensuse-updates/2013-09/msg00043.html
http://rhn.redhat.com/errata/RHSA-2013-1582.html
http://seclists.org/fulldisclosure/2014/Dec/23
http://www.debian.org/security/2014/dsa-2880
http://www.securityfocus.com/archive/1/534161/100/0/threaded

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