The X509Extension in pyOpenSSL before 0.13.1 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 at
The X509Extension in pyOpenSSL before 0.13.1 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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pyopenssl | < 0.13.1 | 0.13.1 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2013-4314
- https://github.com/pyca/pyopenssl/commit/6bbf44a00b35fb28df1f66aa194b2fe95eab1ab2
- https://bugzilla.redhat.com/show_bug.cgi?id=1005325
- https://github.com/pyca/pyopenssl
- https://github.com/pypa/advisory-database/tree/main/vulns/pyopenssl/PYSEC-2013-31.yaml
- https://mail.python.org/pipermail/pyopenssl-users/2013-September/000478.html
- http://lists.opensuse.org/opensuse-updates/2013-11/msg00015.html
- http://www.debian.org/security/2013/dsa-2763
- http://www.openwall.com/lists/oss-security/2013/09/06/2
- http://www.ubuntu.com/usn/USN-1965-1
- https://github.com/advisories/GHSA-6748-36qp-fx6r
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N- Weakness (CWE)
CWE-20- Platform
- Python (PyPI)
- Package
pyopenssl- Disclosed
- 30.09.2013
- Updated
- 11.10.2026 12:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-6748-36qp-fx6r - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2013-31 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: pyopenssl
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 5
- First → latest
- 09.2013 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Low 1
Disclosures per year
- 2017: 0
- 2018: 2
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 2
earlier: 1
-
The X509Extension in pyOpenSSL before 0.13.1 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 at this entry
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