Vulnerability Description
Grav is a flat-file content management system. Prior to version 1.7.42, there is a logic flaw in the `GravExtension.filterFilter()` function whereby validation against a denylist of unsafe functions is only performed when the argument passed to filter is a string. However, passing an array as a callable argument allows the validation check to be skipped. Consequently, a low privileged attacker with login access to Grav Admin panel and page creation/update permissions is able to inject malicious templates to obtain remote code execution. The vulnerability can be found in the `GravExtension.filterFilter()` function declared in `/system/src/Grav/Common/Twig/Extension/GravExtension.php`. Version 1.7.42 contains a patch for this issue. End users should also ensure that `twig.undefined_functions` and `twig.undefined_filters` properties in `/path/to/webroot/system/config/system.yaml` configuration file are set to `false` to disallow Twig from treating undefined filters/functions as PHP functions and executing them.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Getgrav | Grav | < 1.7.42 |
Related Weaknesses (CWE)
References
- https://github.com/getgrav/grav/blob/1.7.40/system/src/Grav/Common/Twig/ExtensioIssue Tracking
- https://github.com/getgrav/grav/blob/1.7.40/system/src/Grav/Common/Utils.php#L19Issue Tracking
- https://github.com/getgrav/grav/commit/244758d4383034fe4cd292d41e477177870b65ecPatch
- https://github.com/getgrav/grav/security/advisories/GHSA-96xv-rmwj-6p9wExploitVendor Advisory
- https://github.com/getgrav/grav/blob/1.7.40/system/src/Grav/Common/Twig/ExtensioIssue Tracking
- https://github.com/getgrav/grav/blob/1.7.40/system/src/Grav/Common/Utils.php#L19Issue Tracking
- https://github.com/getgrav/grav/commit/244758d4383034fe4cd292d41e477177870b65ecPatch
- https://github.com/getgrav/grav/security/advisories/GHSA-96xv-rmwj-6p9wExploitVendor Advisory
FAQ
What is CVE-2023-34252?
CVE-2023-34252 is a vulnerability with a CVSS score of 8.8 (HIGH). Grav is a flat-file content management system. Prior to version 1.7.42, there is a logic flaw in the `GravExtension.filterFilter()` function whereby validation against a denylist of unsafe functions i...
How severe is CVE-2023-34252?
CVE-2023-34252 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2023-34252?
Check the references section above for vendor advisories and patch information. Affected products include: Getgrav Grav.