ChromeWeb browser · Google
CVE-2016-5134
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 · uneditednet/proxy/proxy_service.cc in the Proxy Auto-Config (PAC) feature in Google Chrome before 52.0.2743.82 does not ensure that URL information is restricted to a scheme, host, and port, which allows remote attackers to discover credentials by operating a server with a PAC script, a related issue to CVE-2016-3763.
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 Proxy Auto-Config (PAC) feature in Google Chrome before 52.0.2743.82 was exposing complete URL information (including path and query parameters) instead of restricting URL data to only scheme, host, and port. An attacker controlling a malicious PAC script server could capture sensitive credential information embedded in full URLs accessed by the browser.
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
ChromeWeb browser
<= 51.0.2704.106CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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 Chrome versionNavigate to chrome://version in the browser or run 'google-chrome --version' from command lineAffected if version number is 51.0.2704.106 or lower
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Verify PAC proxy configurationOpen Chrome settings, go to Advanced > Open proxy settings > check PAC script configuration under Connections tab in system proxy settings, or inspect the PAC URL in Chrome's proxy settings at chrome://settingsAffected if a PAC script URL is specified or a PAC file is loaded as the proxy configuration
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Confirm vulnerable URL exposureIf PAC is enabled, inspect the FindProxyForURL(url, host) function in the PAC script - the 'url' parameter would contain full URL with path and query in vulnerable versionsAffected if the PAC script receives and can process complete URLs including path and query parameters rather than only scheme, host, and port
User is affected if Chrome version is 51.0.2704.106 or lower AND a PAC proxy script is configured and active in the browser settings
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 Google Chrome to version 52.0.2743.82 or later, which enforces proper URL data restriction in PAC scripts to only expose scheme, host, and port.
Fix this in Chrome
Scoped from the published advisory
- Consultation1.0 h
- Testing1.0 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 $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-5134 — 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-2016-5134 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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