Public Date:
996381: CVE-2013-4238 python: hostname check bypassing vulnerability in SSL module

The MITRE CVE dictionary describes this issue as:

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.

Find out more about CVE-2013-4238 from the MITRE CVE dictionary dictionary and NIST NVD.


This issue does not affect the version of python as shipped with Red Hat Enterprise Linux 5. The Red Hat Security Response Team has rated this issue as having moderate security impact, a future update may address this flaw.

CVSS v2 metrics

NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.

Base Score 4.3
Base Metrics AV:N/AC:M/Au:N/C:N/I:P/A:N
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact None
Integrity Impact Partial
Availability Impact None

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Red Hat Security Errata

Platform Errata Release Date
Red Hat Enterprise Linux version 6 (python) RHSA-2013:1582 2013-11-20
RHEV Hypervisor for RHEL-6 (rhev-hypervisor6) RHSA-2013:1527 2013-11-21

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 7 python Not affected
Red Hat Enterprise Linux 5 python Not affected