CVE-2021-37626

Workarounds

Disable the login for untrusted back end users.

References

https://contao.org/en/security-advisories/php-file-inclusion-via-insert-tags

For more information

If you have any questions or comments about this advisory, open an issue in contao/contao.

It is possible for untrusted users to load arbitrary PHP files via insert tags.

Installations are only affected if there are untrusted back end users.

Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.

CVE-2021-37626 has a CVSS score of 6.7 (Medium). The vector is network-reachable, high 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 (4.4.56, 4.9.18, 4.11.7); upgrading removes the vulnerable code path.

Kodem intelligence

Update to Contao 4.4.56, 4.9.18 or 4.11.7.

1. What is CVE-2021-37626? CVE-2021-37626 is a medium-severity code injection vulnerability in contao/core-bundle (composer), affecting versions >= 4.0.0, < 4.4.56. It is fixed in 4.4.56, 4.9.18, 4.11.7. Untrusted input is evaluated as executable code within the application's runtime environment.
2. How severe is CVE-2021-37626? CVE-2021-37626 has a CVSS score of 6.7 (Medium). 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 packages are affected by CVE-2021-37626?
   • contao/core-bundle (composer) (versions >= 4.0.0, < 4.4.56)
   • contao/contao (composer) (versions >= 4.0.0, < 4.4.56)
4. Is there a fix for CVE-2021-37626? Yes. CVE-2021-37626 is fixed in 4.4.56, 4.9.18, 4.11.7. Upgrade to this version or later.
5. Is CVE-2021-37626 exploitable, and should I be worried? Whether CVE-2021-37626 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-2021-37626 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-2021-37626?
   • Upgrade contao/core-bundle to 4.4.56 or later
   • Upgrade contao/core-bundle to 4.9.18 or later
   • Upgrade contao/core-bundle to 4.11.7 or later
   • Upgrade contao/contao to 4.4.56 or later
   • Upgrade contao/contao to 4.9.18 or later
   • Upgrade contao/contao to 4.11.7 or later