// For flags

CVE-2023-34252

Grav Server-side Template Injection via Insufficient Validation in filterFilter

Severity Score

7.2
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2023-05-31 CVE Reserved
  • 2023-06-14 CVE Published
  • 2024-07-16 EPSS Updated
  • 2024-08-02 CVE Updated
  • 2024-08-02 First Exploit
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-94: Improper Control of Generation of Code ('Code Injection')
  • CWE-184: Incomplete List of Disallowed Inputs
  • CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Getgrav
Search vendor "Getgrav"
Grav
Search vendor "Getgrav" for product "Grav"
< 1.7.42
Search vendor "Getgrav" for product "Grav" and version " < 1.7.42"
-
Affected