PythonApplication
CVE-2013-7440
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe ssl.match_hostname function in CPython (aka Python) before 2.7.9 and 3.x before 3.3.3 does not properly handle wildcards in hostnames, which might allow man-in-the-middle attackers to spoof servers via a crafted certificate.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe ssl.match_hostname function in Python's standard library (versions before 2.7.9 and 3.x before 3.3.3) contains a flaw in wildcard certificate validation logic. This could allow an attacker with a specially crafted certificate to successfully match a hostname they don't own, enabling man-in-the-middle attacks against SSL/TLS connections.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
PythonApplication
<= 2.7.8= 3.0= 3.0.1= 3.1= 3.1.1= 3.1.2= 3.1.3= 3.1.4= 3.1.5= 3.1.2150= 3.2= 3.2.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Determine the Python interpreter versionRun 'python --version' or 'python3 --version' to get the installed Python versionAffected if Version is 2.7.8 or earlier for Python 2.x, or 3.3.2 or earlier for Python 3.x
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Identify Python scripts using SSL/TLSSearch source code for imports of the ssl module and usage of ssl.wrap_socket, ssl.SSLContext, or ssl.match_hostnameAffected if The codebase uses ssl module functions for certificate validation
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Locate hostname verification callsSearch for calls to ssl.match_hostname or SSLSocket.match_hostname in the codebaseAffected if The application directly calls match_hostname for certificate hostname validation
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Check for wildcard certificate usageReview SSL/TLS configuration or certificate files to identify if wildcard certificates (e.g., *.example.com) are in useAffected if Wildcard certificates are used and the application validates hostnames against them
A user is affected if their Python version is 2.7.8 or earlier (2.x) or 3.3.2 or earlier (3.x) AND the application uses ssl.match_hostname to validate wildcard certificates against hostnames.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade Python to version 2.7.9 or later (for Python 2.x) or 3.3.3 or later (for Python 3.x) to obtain the corrected ssl.match_hostname implementation with proper wildcard handling.
Fix this in Python
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-7440 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2013-7440 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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