PythonApplication
CVE-2016-1000110
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 CGIHandler class in Python before 2.7.12 does not protect against the HTTP_PROXY variable name clash in a CGI script, which could allow a remote attacker to redirect HTTP requests.
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 · high confidenceThe CGIHandler class in Python before 2.7.12 fails to protect against HTTP_PROXY environment variable name clashes in CGI scripts. A remote attacker can inject or override the HTTP_PROXY variable via CGI request headers, potentially redirecting the vulnerable server's outbound HTTP requests through an attacker-controlled proxy.
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
>= 2.7.0, < 2.7.13>= 3.3.0, < 3.3.7>= 3.4.0, < 3.4.6>= 3.5.0, < 3.5.3
Debian LinuxOperating system
= 8.0= 9.0= 10.0
FedoraOperating system
= 23CVSS 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
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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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Check Python versionRun `python --version` or `python3 --version` to determine the installed Python interpreter versionAffected if The version is 2.7.0 to 2.7.12, 3.3.0 to 3.3.6, 3.4.0 to 3.4.5, or 3.5.0 to 3.5.2 (the affected range)
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Identify CGI script usageSearch for CGIHandler references in application code, check for files with .cgi extension, or examine web server configuration for CGI script mappingsAffected if The application uses Python's CGIHandler class to serve CGI scripts
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Inspect HTTP_PROXY exposureSend a test CGI request with an HTTP_PROXY header (e.g., `curl -H 'HTTP_PROXY: http://attacker:8080' http://target/cgi-bin/script.cgi`) and verify if the server passes this header as an environment variableAffected if The HTTP_PROXY header from the request is passed through to the CGI environment without sanitization
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Check for outbound HTTP calls from CGIReview CGI script source code for uses of urllib, urllib2, urllib3, requests, or other HTTP client libraries that respect the HTTP_PROXY environment variableAffected if CGI scripts make outbound HTTP requests using libraries that read the HTTP_PROXY environment variable
You are affected if you run an affected Python version (2.7.0-2.7.12, 3.3.0-3.3.6, 3.4.0-3.4.5, or 3.5.0-3.5.2), use CGIHandler to serve CGI scripts, and those scripts make outbound HTTP requests that could inherit a user-controlled HTTP_PROXY environment variable from CGI request headers.
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 data2.7.133.3.73.4.6
Upgrade to Python 2.7.12 or later, which sanitizes the HTTP_PROXY variable in CGI contexts. Alternatively, avoid using CGI-based handlers or explicitly unset the HTTP_PROXY environment variable before making outbound HTTP requests.
Fix this in Python
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-1000110 — 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-2016-1000110 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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- Version or environment caveats, and links to real fixes
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