CVE-2023-34252
- Reference to the description:
- Description:
- Grav is a file-based Web platform. 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.
- Last updated date:
- 06/23/2023
- Type:
- exploit
- Confidence:
- HIGH
- Date of publishing:
- 06/23/2023
- Reference url to background
https://github.com/getgrav/grav/security/advisories/GHSA-96xv-rmwj-6p9w