CVE-2025-66296: Getgrav/grav Missing Username Uniqueness Check Allows Vulnerability

HIGH
Advisory Identifier: GHSA-cjcp-qxvg-4rjm
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CVSS 8.8
CWE-266
Published
Advisory Summary

CVE-2025-66296 is a HIGH (CVSS 8.8) missing username uniqueness check allows vulnerability (CWE-266: Incorrect Privilege Assignment) affecting Getgrav/grav libraries in the Packagist ecosystem. The issue involves missing username uniqueness check allows admin account takeover. Remediation is available by upgrading affected packages to version 1.8.0-beta.27.

CVE-2025-66296 at a Glance

CVE Identifier CVE-2025-66296
GHSA Identifier GHSA-cjcp-qxvg-4rjm
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-266: Incorrect Privilege Assignment
Affected Product Getgrav/grav
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2025-66296

To remediate this vulnerability, upgrade all affected Getgrav/grav dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

getgrav/grav fixed: 1.8.0-beta.27 
Upgrade getgrav/grav to 1.8.0-beta.27
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for getgrav/grav

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-66296, inspect your project dependencies for Getgrav/grav:

inspect dependencies for getgrav/grav

Analyze the terminal output to locate any version of Getgrav/grav in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.8.0-beta.27), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-266: Incorrect Privilege Assignment, where a product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor. In Getgrav/grav, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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

CVE-2025-66296 Affected Getgrav/grav Versions

1 component(s)
Fixed Versions:
1.8.0-beta.27
Product / Package Ecosystem Affected Versions Fixed Version
getgrav/grav
 Packagist
< 1.8.0-beta.27
1.8.0-beta.27

References

GitHub Advisory / Wiki ADVISORY
https://github.com/getgrav/grav/security/advisories/GHSA-cjcp-qxvg-4rjm
NVD — CVE-2025-66296 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-66296
Security Fix Commit FIX COMMIT
https://github.com/getgrav/grav/commit/3462d94d575064601689b236508c316242e15741
Getgrav/grav Source Repository REPOSITORY
https://github.com/getgrav/grav

Frequently Asked Questions

What is CVE-2025-66296?
CVE-2025-66296 is a security vulnerability in Getgrav/grav involving Missing Username Uniqueness Check Allows Admin Account Takeover under CWE-266: Incorrect Privilege Assignment.
Which Getgrav/grav versions are affected?
Affected versions include releases prior to 1.8.0-beta.27 across affected packages: getgrav/grav.
What version fixes CVE-2025-66296?
Upgrading to 1.8.0-beta.27 (or the latest patched release for your respective branch) resolves the vulnerability.
Is getgrav/grav affected?
Yes, getgrav/grav is affected in releases prior to 1.8.0-beta.27. Upgrade your dependency to 1.8.0-beta.27 or later.
What is the CVSS score of CVE-2025-66296?
CVE-2025-66296 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2025-66296?
CVE-2025-66296 is classified under CWE-266: Incorrect Privilege Assignment (A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor.).
How can I check Packagist dependencies for CVE-2025-66296?
Run the dependency tree command: 'inspect dependencies for getgrav/grav'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-cjcp-qxvg-4rjm",
  "modified" : "2025-12-02T00:35:19Z",
  "published" : "2025-12-02T00:35:18Z",
  "aliases" : [ "CVE-2025-66296" ],
  "summary" : "Grav vulnerable to Privilege Escalation in Grav Admin: Missing Username Uniqueness Check Allows Admin Account Takeover",
  "details" : "### Summary\nA privilege escalation vulnerability exists in Grav’s Admin plugin due to the absence of username uniqueness validation when creating users.\nA 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.\n\n\n### Steps to Reproduce\n1. Make sure you have two accounts: an admin and a user with create user privilege\n2. In the user account, navigate to /grav-admin/admin/accounts/users and click \"Add\"\n3. Enter the name of the admin, complete registration and observe that the existing admin’s email is changed to the value you provided.\n4. Log out from user account log in as admin with new credentials\n\n\n### Impact\n1. Full admin takeover by any user with create user permission.\n2. Ability to change admin credentials, install/remove plugins, read or modify site data, and execute any action available to an admin.\n3. Severity: High/Critical.\n\n\n### PoC\nhttps://github.com/user-attachments/assets/3ab0a7d6-5055-41be-9e0e-2bd6ca359b37",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "getgrav/grav"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.8.0-beta.27"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/getgrav/grav/security/advisories/GHSA-cjcp-qxvg-4rjm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-66296"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/getgrav/grav/commit/3462d94d575064601689b236508c316242e15741"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/getgrav/grav"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-266" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-02T00:35:18Z",
    "nvd_published_at" : "2025-12-01T21:15:53Z"
  }
}