dbcve.org
LibproxyApplication · Libproxy Project

CVE-2012-4504

HIGH · 10.0 CVSS v2.0 Published 2012-11-11
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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 · unedited
Stack-based buffer overflow in the url::get_pac function in url.cpp in libproxy 0.4.x before 0.4.9 allows remote servers to have an unspecified impact via a large proxy.pac file.

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 confidence

Stack-based buffer overflow in the url::get_pac function in url.cpp in libproxy 0.4.x before 0.4.9 allows remote servers to execute arbitrary code via a specially crafted large proxy.pac file. The vulnerability occurs when parsing the PAC (Proxy Auto-Config) file without proper bounds checking.

MitigationUpgrade libproxy to version 0.4.9 or later to obtain the patch that adds proper bounds checking in the url::get_pac function. If upgrading is not immediately possible, restrict network access to trusted proxy servers and validate PAC file sizes before processing.

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
LibproxyApplication
Affected:= 0.4.0= 0.4.1= 0.4.2= 0.4.3= 0.4.5= 0.4.6= 0.4.7= 0.4.8

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed libproxy version
    Run 'dpkg -l libproxy1' (Debian/Ubuntu) or 'rpm -q libproxy' (RHEL/CentOS) or check your system's package manager for the libproxy package version
    Affected if Version is 0.4.0, 0.4.1, 0.4.2, 0.4.3, 0.4.5, 0.4.6, 0.4.7, or 0.4.8
  2. Identify applications using libproxy
    Search for binaries that link against libproxy using 'ldd' or check /usr/lib/libproxy* files, or look for proxy configuration tools that depend on libproxy
    Affected if Any application using libproxy for proxy configuration is present and PAC file handling is enabled
  3. Verify PAC file parsing is in use
    Check system or application proxy settings for 'pac' or 'Proxy Auto-Config' file references, typically in environment variables (http_proxy, https_proxy, no_proxy or GNOME/KDE network proxy settings) pointing to a .pac URL or file
    Affected if Proxy configuration points to a PAC file or URL that libproxy would process via the url::get_pac function
  4. Inspect PAC file handling configuration
    Look for proxy.pac files in common locations like /etc/proxy.pac, ~/.proxy.pac, or check browser/network settings for PAC URL configurations
    Affected if Large or untrusted PAC files are being loaded by the system

You are affected if libproxy version 0.4.0-0.4.8 is installed AND applications use libproxy to process PAC files for proxy configuration.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch code.google.com →
Interim mitigation

Upgrade libproxy to version 0.4.9 or later to obtain the patch that adds proper bounds checking in the url::get_pac function. If upgrading is not immediately possible, restrict network access to trusted proxy servers and validate PAC file sizes before processing.

Recommended fix High confidence

libproxy 0.4.9 or later

  1. Identify the current installed version of libproxy using your system's package manager or by checking the binary
  2. Upgrade libproxy to version 0.4.9 or later via your system's package manager (e.g., apt-get update && apt-get install libproxy, yum update libproxy, or equivalent)
  3. Alternatively, download libproxy 0.4.9 or later from the official source and rebuild/install
  4. Verify the installed version is 0.4.9 or later using 'pkg-config --modversion libproxy' or equivalent

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Libproxy Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
8.0 hours of engineering $1,370
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,192.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2012-4504 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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