CVE-2012-4505
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 · uneditedHeap-based buffer overflow in the px_pac_reload function in lib/pac.c in libproxy 0.2.x and 0.3.x allows remote servers to have an unspecified impact via a crafted Content-Length size in an HTTP response header for a proxy.pac file request, a different vulnerability than CVE-2012-4504.
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 confidenceHeap-based buffer overflow in libproxy's px_pac_reload function (lib/pac.c) allows remote servers to overflow the heap via a specially crafted Content-Length HTTP header when serving proxy.pac files. The vulnerability affects versions 0.2.x and 0.3.x and could allow arbitrary code execution or denial of service.
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= 0.2.3= 0.3.0= 0.3.1CVSS 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
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:L/Au:N/C:C/I:C/A:C
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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Identify installed libproxy versionRun 'pkg-config --modversion libproxy' or check your system's package manager for libproxy version (e.g., 'dpkg -l | grep libproxy' on Debian/Ubuntu, 'rpm -q libproxy' on RHEL/CentOS)Affected if Version is 0.2.3, 0.3.0, or 0.3.1 exactly, or falls within 0.2.x or 0.3.x ranges
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Verify proxy.pac file configurationCheck for proxy.pac URL configuration in system proxy settings, environment variables (HTTP_PROXY, HTTPS_PROXY, FTP_PROXY), or network configuration files that point to HTTP URLs for PAC filesAffected if A remote HTTP URL is configured for proxy.pac retrieval (e.g., http://server/proxy.pac)
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Inspect PAC file fetching mechanismReview application or system logs for libproxy activity when fetching proxy.pac files via HTTP, or examine the libproxy configuration files in /etc/libproxy/ or ~/.config/libproxy/Affected if The system uses libproxy to fetch PAC files over HTTP from remote servers
You are affected if libproxy version 0.2.3, 0.3.0, or 0.3.1 (or any 0.2.x/0.3.x version) is installed AND remote HTTP-fetched proxy.pac files are in use.
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 libproxy to a patched version, or use local proxy.pac files instead of remote HTTP-fetched ones. Implement strict validation of Content-Length header values before heap allocation.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-4505 — 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-2012-4505 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
- No weaponised exploit code, or anything meant to cause harm
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