Summary
Symfony Allows URI Restrictions Bypass Via Double-Encoded String
On the Symfony 2.0.x version, there's a security issue that allows access to routes protected by a firewall even when the user is not logged in.
Both the Routing component and the Security component uses the path returned by getPathInfo() to match a Request. The getPathInfo() returns a decoded path, but the Routing component (Symfony\Component\Routing\Matcher\UrlMatcher) decodes the path a second time; whereas the Security component, Symfony\Component\HttpFoundation\RequestMatcher, does not.
This difference causes Symfony 2.0 to be vulnerable to double encoding attacks.
Impact
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
symfony/http-foundation to 2.0.19 or later; symfony/routing to 2.0.19 or later; symfony/security to 2.0.19 or later; symfony/symfony to 2.0.19 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2012-6431? CVE-2012-6431 is a medium-severity improper authentication vulnerability in symfony/http-foundation (composer), affecting versions >= 2.0.0, < 2.0.19. It is fixed in 2.0.19. The application does not adequately verify the identity of a user, device, or process before granting access.
- Which packages are affected by CVE-2012-6431?
symfony/http-foundation(composer) (versions >= 2.0.0, < 2.0.19)symfony/routing(composer) (versions >= 2.0.0, < 2.0.19)symfony/security(composer) (versions >= 2.0.0, < 2.0.19)symfony/symfony(composer) (versions >= 2.0.0, < 2.0.19)
- Is there a fix for CVE-2012-6431? Yes. CVE-2012-6431 is fixed in 2.0.19. Upgrade to this version or later.
- Is CVE-2012-6431 exploitable, and should I be worried? Whether CVE-2012-6431 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2012-6431 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2012-6431?
- Upgrade
symfony/http-foundationto 2.0.19 or later - Upgrade
symfony/routingto 2.0.19 or later - Upgrade
symfony/securityto 2.0.19 or later - Upgrade
symfony/symfonyto 2.0.19 or later
- Upgrade