CVE-2025-66296

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

PoC

https://github.com/user-attachments/assets/3ab0a7d6-5055-41be-9e0e-2bd6ca359b37

1. Full admin takeover by any user with create user permission.
2. Ability to change admin credentials, install/remove plugins, read or modify site data, and execute any action available to an admin.
3. Severity: High/Critical.

CVE-2025-66296 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.8.0-beta.27); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-66296? CVE-2025-66296 is a high-severity security vulnerability in getgrav/grav (composer), affecting versions < 1.8.0-beta.27. It is fixed in 1.8.0-beta.27.
2. How severe is CVE-2025-66296? CVE-2025-66296 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of getgrav/grav are affected by CVE-2025-66296? getgrav/grav (composer) versions < 1.8.0-beta.27 is affected.
4. Is there a fix for CVE-2025-66296? Yes. CVE-2025-66296 is fixed in 1.8.0-beta.27. Upgrade to this version or later.
5. Is CVE-2025-66296 exploitable, and should I be worried? Whether CVE-2025-66296 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-66296 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-66296? Upgrade getgrav/grav to 1.8.0-beta.27 or later.