Description

The MultiVendorX WordPress plugin before 5.0.16 does not restrict who can update its role and capability settings, allowing users holding its vendor role to grant that role administrator-level capabilities and take over the site.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.2",
  "pubDate": "2026-09-11T07:16:46.740Z",
  "pubdate": "2026-09-11T07:16:46.740Z",
  "executiveSummary": "The MultiVendorX WordPress plugin prior to version 5.0.16 is susceptible to an authorization bypass vulnerability.\nThe vulnerability originates from a lack of server-side access control validation when modifying user role and capability configurations.\nAn authenticated user assigned the 'vendor' role can manipulate system settings to grant themselves administrator-level privileges.\nThis flaw effectively allows a low-privileged vendor to achieve full administrative control over the WordPress installation, leading to complete site compromise.\nThe attack requires an existing account with the vendor role, posing a significant risk in multi-vendor environments where users are not trusted.\nNo complex exploitation vectors are required, as the application fails to verify the requestor's authorization before applying configuration changes.",
  "technicalDetails": "The vulnerability resides in the role and capability management component of the MultiVendorX plugin. The plugin fails to implement adequate permission checks on the endpoints responsible for updating or assigning user roles and capabilities.\nIn a secure implementation, any request to modify role capabilities must be strictly gated by server-side checks to ensure that the current user possesses the 'manage_options' or equivalent high-level administrative capability.\nIn the affected versions (prior to 5.0.16), the internal logic responsible for handling role updates does not perform a robust validation of the user's role before processing the requested changes. Consequently, a user authenticated with the 'vendor' role can send specifically crafted HTTP requests to the plugin's configuration endpoints.\nThe attack flow proceeds as follows: First, the attacker authenticates as a legitimate vendor. Second, the attacker interacts with the plugin's configuration interface or sends direct POST requests to the vulnerable settings API. Because the backend fails to validate the caller's session permissions against the sensitive nature of role modification, the plugin accepts the request to alter capability definitions.\nBy modifying the capability mapping associated with the vendor role, the attacker can append administrator-level capabilities (e.g., 'manage_options', 'activate_plugins', 'edit_users') to their own role. Upon updating these settings, the plugin propagates these changes to the WordPress roles and capabilities system (via update_option('wp_user_roles', ...)).\nOnce the vendor role is updated with administrative privileges, the attacker gains the ability to execute unauthorized administrative actions, including installing or activating malicious plugins, modifying system configurations, accessing database content, and potentially achieving Remote Code Execution (RCE) on the underlying server. This constitutes a full account and site takeover, moving from a standard vendor account to a site administrator."
}