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

High severity GitHub Reviewed Published Dec 1, 2025 in getgrav/grav • Updated Dec 2, 2025

Package

composer getgrav/grav (Composer)

Affected versions

< 1.8.0-beta.27

Patched versions

1.8.0-beta.27

Description

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 data, and execute any action available to an admin.
  3. Severity: High/Critical.

PoC

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

References

@rhukster rhukster published to getgrav/grav Dec 1, 2025
Published by the National Vulnerability Database Dec 1, 2025
Published to the GitHub Advisory Database Dec 2, 2025
Reviewed Dec 2, 2025
Last updated Dec 2, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(9th percentile)

Weaknesses

Incorrect Privilege Assignment

A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor. Learn more on MITRE.

CVE ID

CVE-2025-66296

GHSA ID

GHSA-cjcp-qxvg-4rjm

Source code

Credits

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