CVE-2016-6287
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 "http-client" egg always used a HTTP_PROXY environment variable to determine whether HTTP traffic should be routed via a proxy, even when running as a CGI process. Under several web servers this would mean a user-supplied "Proxy" header could allow an attacker to direct all HTTP requests through a proxy (also known as a "httpoxy" attack). This affects all versions of http-client before 0.10.
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 http-client egg for Chicken Scheme unconditionally uses the HTTP_PROXY environment variable to determine proxy settings, even when running as a CGI process. In CGI contexts, the HTTP_PROXY env var can be set from the incoming 'Proxy' HTTP header, allowing attackers to redirect all HTTP requests through an attacker-controlled proxy (httpoxy attack). This affects versions before 0.10.
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<= 0.9CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/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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Check installed http-client egg versionUse chicken-install to list installed eggs and their versions, or inspect the egg's metadata file in the Chicken Scheme library directoryAffected if The http-client egg version is 0.9 or lower (any version before 0.10)
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Identify if the application runs as a CGI processCheck for common CGI environment variables such as REQUEST_METHOD, SERVER_PROTOCOL, or GATEWAY_INTERFACE being set in the process environmentAffected if The application runs as a CGI process and these CGI-specific environment variables are present
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Verify HTTP_PROXY environment variable is setInspect the process environment for the HTTP_PROXY variable using commands like 'env' or 'printenv'Affected if The HTTP_PROXY environment variable is present and exported in the environment
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Confirm http-client uses HTTP_PROXY for proxy settingsReview application code or http-client egg source to verify it reads HTTP_PROXY for proxy configuration without validating whether the application runs in CGI contextAffected if The http-client egg unconditionally uses HTTP_PROXY for proxy settings without checking for CGI execution context
You are affected if you run http-client egg version 0.9 or earlier in a CGI context while the HTTP_PROXY environment variable is present, allowing an attacker to inject a Proxy header to redirect your HTTP requests.
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 to http-client version 0.10 or later, which should implement proper validation to ignore user-supplied Proxy headers when running in CGI environments, or explicitly unset HTTP_PROXY in CGI deployments.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2016-6287 — 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-2016-6287 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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