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.
CVE-2013-4314
This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 4.3 — v2 rates that MEDIUM (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:N/AC:M/Au:N/C:N/I:P/A:N. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 1.2% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v2.0 (legacy)
- 4.3MEDIUMNVD never assigned a CVSS v3 rating to this CVE
- EG Score
- 4.3(low)
- EG Risk
- 24(Track)EG Risk 24/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity43% × 45%Exploitation1% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 65%
- KEV
- Not listed
Published
September 30, 2013
Last Modified
April 29, 2026
References (12)
- secalert@redhathttp://lists.opensuse.org/opensuse-updates/2013-11/msg00015.html
- secalert@redhathttp://www.debian.org/security/2013/dsa-2763
- secalert@redhathttp://www.openwall.com/lists/oss-security/2013/09/06/2
- secalert@redhathttp://www.ubuntu.com/usn/USN-1965-1
- secalert@redhathttps://bugzilla.redhat.com/show_bug.cgi?id=1005325
- secalert@redhathttps://mail.python.org/pipermail/pyopenssl-users/2013-September/000478.html
- af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-updates/2013-11/msg00015.html
- af854a3a-2127-422b-91ae-364da2661108http://www.debian.org/security/2013/dsa-2763
- af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2013/09/06/2
- af854a3a-2127-422b-91ae-364da2661108http://www.ubuntu.com/usn/USN-1965-1
- af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=1005325
- af854a3a-2127-422b-91ae-364da2661108https://mail.python.org/pipermail/pyopenssl-users/2013-September/000478.html
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python3-openssl (0.13-2ubuntu1.1) @ quantal | 2026-05-28 | ubuntu |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| pyopenssl | 0.10 ... 0.9 (8 versions) | 0.13.1 | — |
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 12× in last 7d / 38× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 104 total refreshes for this CVE.
- 2026-07-26 13:48 UTCEG score recompute▲ 4.30
- 2026-07-25 14:12 UTCEPSS rescore
- 2026-07-23 14:14 UTCEPSS rescore
- 2026-07-23 01:10 UTCEG score recompute
- 2026-07-23 00:13 UTCEG score recompute
- 2026-07-22 21:52 UTCEG score recompute
- 2026-07-22 14:04 UTCEPSS rescore
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- 2026-07-22 10:48 UTCOSV refresh
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- 2026-07-08 15:10 UTCEPSS rescore
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- 2026-06-16 17:09 UTCOSV refresh
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- 2026-05-29 13:41 UTCEPSS rescore
- 2026-05-29 13:41 UTCEPSS rescore
- 2026-05-28 22:17 UTCEG score recompute
- 2026-05-28 22:17 UTCVendor advisory
- 2026-05-28 13:42 UTCEPSS rescore
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Frequently asked(4)
What is CVE-2013-4314?
When was CVE-2013-4314 disclosed?
Is CVE-2013-4314 actively exploited?
How do I remediate CVE-2013-4314?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2013-4314
Is Your Infrastructure Affected by CVE-2013-4314?
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