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medium 4.3

CVE-2013-4238 json

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 t…

published 13y ago modified 4mo ago also EUVD-2013-4142

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.3%
EPSS 5.3% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

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.

Patch / fix

  • python2.7 Debian 11 2.7.5-8

debian advisories DEBIAN-CVE-2013-4238

  • python RHEL 6 2.6.6-51.el6
  • tkinter RHEL 6 2.6.6-51.el6
  • python-libs RHEL 6 2.6.6-51.el6
  • python-test RHEL 6 2.6.6-51.el6
  • python-tools RHEL 6 2.6.6-51.el6
  • rhev-hypervisor6 RHEL 6 6.5-20131115.0.3.2.el6_5

red hat advisories RHSA-2013:1582RHSA-2013:1527

  • python SLE Module for Python 2 15 SP1, SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 +2 more 2.7.17-7.32.2
  • python-base SLE Module for Python 2 15 SP1, SLE Module for Basesystem 15 SP1, SLE Module for Basesystem 15 2.7.17-7.32.1
  • python3 SLE Module for Basesystem 15 SP1, SLE Module for Basesystem 15 3.6.10-3.42.2
  • python3-base SLE Module for Development Tools 15 SP1, SLE Module for Development Tools 15, SLE Module for Basesystem 15 SP1 +1 more 3.6.10-3.42.2

suse advisories SUSE-SU-2020:0234-1SUSE-SU-2020:0114-1

  • python315 openSUSE Tumbleweed 3.15.0~a1-1.1
  • python314 openSUSE Tumbleweed 3.14.0~a1-1.1
  • python313 openSUSE Tumbleweed 3.13.0~b3-1.1
  • python3 openSUSE Tumbleweed 3.5.1-3.8
  • python openSUSE Tumbleweed 2.7.12-1.5
  • python-base openSUSE Tumbleweed 2.7.12-1.4
  • python310 openSUSE Tumbleweed 3.10.0rc1-4.2
  • python36 openSUSE Tumbleweed 3.6.15-1.1

opensuse advisories openSUSE-SU-2025:15713-1openSUSE-SU-2024:14434-1openSUSE-SU-2024:14109-1openSUSE-SU-2024:10100-1openSUSE-SU-2024:10450-1openSUSE-SU-2024:10536-1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2013-4238 updated cvss 4.3

python: hostname check bypassing vulnerability in SSL module

  • Red Hat Enterprise Linux Desktop (v. 6) python 2.6.6-51.el6, tkinter 2.6.6-51.el6, python-libs 2.6.6-51.el6 Red Hat Enterprise Linux Desktop Optional (v. 6) python 2.6.6-51.el6, python-test 2.6.6-51.el6, python-tools 2.6.6-51.el6 Red Hat Enterprise Linux HPC Node (v. 6) python 2.6.6-51.el6, python-libs 2.6.6-51.el6 Red Hat Enterprise Linux HPC Node Optional (v. 6) python 2.6.6-51.el6, tkinter 2.6.6-51.el6, python-test 2.6.6-51.el6, python-tools 2.6.6-51.el6 Red Hat Enterprise Linux Server (v. 6) python 2.6.6-51.el6, tkinter 2.6.6-51.el6, python-libs 2.6.6-51.el6 Red Hat Enterprise Linux Server Optional (v. 6) python 2.6.6-51.el6, tkinter 2.6.6-51.el6, python-test 2.6.6-51.el6, python-tools 2.6.6-51.el6
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 6) python 2.6.6-51.el6, tkinter 2.6.6-51.el6, python-libs 2.6.6-51.el6 Red Hat Enterprise Linux Workstation Optional (v. 6) python 2.6.6-51.el6, python-test 2.6.6-51.el6, python-tools 2.6.6-51.el6
    fixed: vendor fix RHSA-2013:1582
  • Red Hat RHEV Hypervisor for RHEL-6 rhev-hypervisor6 6.5-20131115.0.3.2.el6_5
    fixed: vendor fix RHSA-2013:1527
  • Red Hat Enterprise Linux 5 python Red Hat Enterprise Linux 7 python, tkinter, python-libs, python-test, python-tools Red Hat Software Collections python27-python, python33-python, python27-tkinter, python27-python-libs, python27-python-test, python33-python-libs, +4 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

5.35% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.