Grav has Broken Access Control which allows an Editor to modify the page's YAML Frontmatter to alter form processing actions

Exploitation

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

CVSS 4.0

8.6 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2025-66301: 1.43% estimated exploitation activity in the next 30 days; percentile 73.11 (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 a broken access control vulnerability in the /admin/pages/{pagename} endpoint, an editor ( user with full permissions to pages ) can change the functionality of a form after submission. Details Due to improper authorization checks when modifying critical fields on a POST request to /admin/pages/{pagename}, an editor with only permissions to change basic content on the form is now able to change the functioning of the form through modifying the content of the data[json][header][form] which is the YAML frontmatter which includes the process section which dictates what happens after a user submits the form which include some important actions that could lead to further vulnerabilities. PoC - Have Admin and Form plugins installed - Connect to panel as admin, create user and give him permission for pages all - Now connect as that user and notice you cant edit any process field in the panel - Change anything in the content of the form and save - Intercept the request: - Now…

Published by the source

2 Dec 2025, 00:36 UTC

Last modified by the source

2 Dec 2025, 00:36 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v8x2-fjv7-8hjh

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2025-66301

Advisory: Grav has Broken Access Control which allows an Editor to modify the page's YAML Frontmatter to alter form processing actions
IDs: CVE-2025-66301, GHSA-v8x2-fjv7-8hjh
Record: https://patchnext.com/advisories/cve-2025-66301 (revision 1, source checked 26 Oct 2026, 14:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: getgrav/grav 1.8.0-beta.27. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist getgrav/grav: affected < 1.8.0-beta.27; fixed in 1.8.0-beta.27

## 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-v8x2-fjv7-8hjh (GitHub-reviewed advisory GHSA-v8x2-fjv7-8hjh lists affected ranges: Packagist getgrav/grav >=0 <1.8.0-beta.27)

Commands are suggestions: review each one before running it.