CVE Catalog

CVE-2023-34252

HighCVSS 8.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

High risk
2.07%

79th percentile - higher than 79% of all known CVEs

Summary

Grav is a flat-file content management system. Prior to version 1.7.42, there is a logic flaw in the `GravExtension.filterFilter()` function that allows validation against a denylist of unsafe functions to be skipped when an array is passed as an argument. This enables a low privileged attacker with login access to the Grav Admin panel and page creation/update permissions to inject malicious templates and obtain remote code execution.

Risk Assessment

An attacker with access to the Grav admin panel and permissions to create/update pages can exploit this vulnerability to inject malicious code, posing a serious security threat to the system.

Recommendation

It is recommended to upgrade to version 1.7.42 or later and ensure that the `twig.undefined_functions` and `twig.undefined_filters` properties in the `system.yaml` configuration file are set to `false`.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS