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Public proof of conceptFix available

CVE-2023-34252

A public proof of concept exists; no exploitation attested.

  • Published2023-06-14
  • Fixed in1.7.42
  • WeaknessCWE-1336 · CWE-184 · CWE-94

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2023-06-1422:15CVE publishedNVD

Versions per branch

NVD · OSV
Getgrav grav
BranchAffectedFixed in
1.7< 1.7.421.7.42

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • getgrav grav
    Affected
    • = < 1.7.42no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2023-06-14

Fix

  1. Update Getgrav grav to 1.7.42

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2024-12-18
  • CNACVSS 3.18.8known since 2026-10-23
  • NVDCVSS 3.17.2read 2026-10-23
  • CNAweakness (CWE)CWE-1336, CWE-184known since 2026-10-23
  • NVDweakness (CWE)CWE-94read 2026-10-23
  • FIRST EPSSEPSS score2.1 %2026-11-09
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2023-06-16

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Published
2023-06-14
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-96xv-rmwj-6p9w

Frequently asked questions

What is CVE-2023-34252?

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.

Is CVE-2023-34252 actively exploited?

A proof-of-concept exploit exists for CVE-2023-34252, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2023-34252?

CVE-2023-34252 has a CVSS v3 base score of 7.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

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