SymfonyFramework / library · Sensiolabs
CVE-2012-6431
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 · uneditedSymfony 2.0.x before 2.0.20 does not process URL encoded data consistently within the Routing and Security components, which allows remote attackers to bypass intended URI restrictions via a doubly encoded string.
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 confidenceSymfony 2.0.x before 2.0.20 has an inconsistent URL encoding processing vulnerability in its Routing and Security components. Attackers can bypass intended URI restrictions by using doubly-encoded strings (e.g., %252e%252f for ../), allowing path traversal or unauthorized access to protected routes.
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
SymfonyFramework / library
= 2.0.0= 2.0.1= 2.0.2= 2.0.3= 2.0.4= 2.0.5= 2.0.6= 2.0.7= 2.0.8= 2.0.9= 2.0.10= 2.0.11CVSS 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
- Partial
- Integrity
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:P/I:P/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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Determine installed Symfony versionLocate the Symfony vendor directory or version file. In a Symfony 2.0 project, check the vendor/symfony/symfony/composer.json file or run 'composer show symfony/symfony' if Composer is available. The version is typically listed in the 'version' or 'version_normalized' field.Affected if The installed version is 2.0.0 through 2.0.11 (any 2.0.x version before 2.0.20)
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Verify Routing component is in useCheck the app/AppKernel.php file for the presence of the Symfony Bundle 'Symfony\Component\Routing\DependencyInjection\RoutingExtension' or verify that the routing component is loaded in your application configuration.Affected if The Routing component is loaded and processes user-supplied URLs without prior normalization
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Verify Security component is in useCheck the security configuration (app/config/security.yml) to confirm the Security component is active and protecting routes or resources.Affected if The Security component is active and relies on URI matching for access control
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Check for URL normalization at web server levelInspect your web server configuration (Apache .htaccess, nginx config, or equivalent) for any input validation rules that normalize or reject double-encoded sequences like %252e or %252f.Affected if No such normalization exists and the application relies solely on Symfony's built-in request processing
You are affected if your Symfony installation version is 2.0.0 through 2.0.11 and the Routing or Security components are active without any external normalization layer filtering double-encoded URLs.
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 Symfony to version 2.0.20 or later, which contains the patched URL encoding handling. Alternatively, implement input validation that normalizes and rejects doubly-encoded sequences at the web server level.
Fix this in Symfony
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 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 $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-6431 — 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-2012-6431 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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