Remote Code Execution by uploading a phar file using frontmatter

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2024-27923: 1.36% estimated exploitation activity in the next 30 days; percentile 71.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary - Due to insufficient permission verification, user who can write a page use frontmatter feature. - Inadequate File Name Validation Details 1. Insufficient Permission Verification In Grav CMS, "Frontmatter" refers to the metadata block located at the top of a Markdown file. Frontmatter serves the purpose of providing additional information about a specific page or post. In this feature, only administrators are granted access, while regular users who can create pages are not. However, if a regular user adds the data[json][header][form] parameter to the POST Body while creating a page, they can use Frontmatter. The demonstration of this vulnerability is provided in video format. Video Link 2. Inadequate File Name Validation To create a Contact Form, Frontmatter and markdown can be written as follows: Contact Form Example Form Action Save Option When an external user submits the Contact Form after filling it out, the data is stored in the user/data folder. The filename under…

Published by the source

6 Mar 2024, 16:58 UTC

Last modified by the source

17 Feb 2026, 19:39 UTC

Source last checked

26 Oct 2026, 14:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-f6g2-h7qv-3m5v

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# Patch Next advisory brief: CVE-2024-27923

Advisory: Remote Code Execution by uploading a phar file using frontmatter
IDs: CVE-2024-27923, GHSA-f6g2-h7qv-3m5v
Record: https://patchnext.com/advisories/cve-2024-27923 (revision 1, source checked 26 Oct 2026, 14:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: getgrav/grav 1.7.43. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist getgrav/grav: affected < 1.7.43; fixed in 1.7.43

## Suggested inspection (read-only)
- Packagist getgrav/grav: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on getgrav/grav.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-f6g2-h7qv-3m5v (GitHub-reviewed advisory GHSA-f6g2-h7qv-3m5v lists affected ranges: Packagist getgrav/grav >=0 <1.7.43)

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