Grav vulnerable to Privilege Escalation in Grav Admin: Missing Username Uniqueness Check Allows Admin Account Takeover

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-2025-66296: 0.34% estimated exploitation activity in the next 30 days; percentile 27.62 (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 A privilege escalation vulnerability exists in Grav’s Admin plugin due to the absence of username uniqueness validation when creating users. A user with the create user permission can create a new account using the same username as an existing administrator account, set a new password/email, and then log in as that administrator. This effectively allows privilege escalation from limited user-manager permissions to full administrator access. Steps to Reproduce 1. Make sure you have two accounts: an admin and a user with create user privilege 2. In the user account, navigate to /grav-admin/admin/accounts/users and click "Add" 3. Enter the name of the admin, complete registration and observe that the existing admin’s email is changed to the value you provided. 4. Log out from user account log in as admin with new credentials Impact 1. Full admin takeover by any user with create user permission. 2. Ability to change admin credentials, install/remove plugins, read or modify site…

Published by the source

2 Dec 2025, 00:35 UTC

Last modified by the source

2 Dec 2025, 00:35 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cjcp-qxvg-4rjm

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

# Patch Next advisory brief: CVE-2025-66296

Advisory: Grav vulnerable to Privilege Escalation in Grav Admin: Missing Username Uniqueness Check Allows Admin Account Takeover
IDs: CVE-2025-66296, GHSA-cjcp-qxvg-4rjm
Record: https://patchnext.com/advisories/cve-2025-66296 (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 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: getgrav/grav 1.8.0-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-cjcp-qxvg-4rjm (GitHub-reviewed advisory GHSA-cjcp-qxvg-4rjm lists affected ranges: Packagist getgrav/grav >=0 <1.8.0-beta.27)

Commands are suggestions: review each one before running it.