CVE-2024-51996

Symfony has an Authentication Bypass via RememberMe

Description

When consuming a persisted remember-me cookie, Symfony does not check if the username persisted in the database matches the username attached with the cookie, leading to authentication bypass.

Resolution

The PersistentRememberMeHandler class now ensures the submitted username is the cookie owner.

The patch for this issue is available here for branch 5.4.

Credits

We would like to thank Moritz Rauch - Pentryx AG for reporting the issue and Jérémy Derussé for providing the fix.

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.

CVE-2024-51996 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.4.47, 6.4.15, 7.1.8); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2024-51996? CVE-2024-51996 is a high-severity improper authentication vulnerability in symfony/security-http (composer), affecting versions >= 5.3.0, < 5.4.47. It is fixed in 5.4.47, 6.4.15, 7.1.8. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2024-51996? CVE-2024-51996 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of symfony/security-http are affected by CVE-2024-51996? symfony/security-http (composer) versions >= 5.3.0, < 5.4.47 is affected.
4. Is there a fix for CVE-2024-51996? Yes. CVE-2024-51996 is fixed in 5.4.47, 6.4.15, 7.1.8. Upgrade to this version or later.
5. Is CVE-2024-51996 exploitable, and should I be worried? Whether CVE-2024-51996 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
6. What actually determines whether CVE-2024-51996 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.
7. How do I fix CVE-2024-51996?
   • Upgrade symfony/security-http to 5.4.47 or later
   • Upgrade symfony/security-http to 6.4.15 or later
   • Upgrade symfony/security-http to 7.1.8 or later

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