CVE-2025-39434 Overview
CVE-2025-39434 is an Insecure Direct Object Reference (IDOR) vulnerability in the Scott Taylor Avatar WordPress plugin. The flaw affects all versions from initial release through 0.1.4. Authenticated attackers with low privileges can manipulate user-controlled keys to bypass access control checks. The vulnerability is categorized under [CWE-639] Authorization Bypass Through User-Controlled Key. Exploitation occurs over the network without user interaction, allowing an attacker to modify resources belonging to other users.
Critical Impact
Authenticated attackers can bypass authorization controls to access or modify avatar-related resources belonging to other WordPress users on affected sites.
Affected Products
- Scott Taylor Avatar WordPress plugin versions up to and including 0.1.4
- WordPress installations with the Avatar plugin enabled
- Sites permitting low-privilege authenticated user registration
Discovery Timeline
- 2025-04-17 - CVE-2025-39434 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-39434
Vulnerability Analysis
The Scott Taylor Avatar plugin fails to validate that the currently authenticated user owns the object referenced by a request parameter. When the plugin processes avatar-related actions, it accepts an identifier supplied by the client and acts on the corresponding record without confirming ownership. This design allows an authenticated user to substitute another user's identifier and manipulate resources outside their authorization scope.
The issue is classified as [CWE-639] Authorization Bypass Through User-Controlled Key. Access control decisions rely on a value the attacker fully controls, rather than on server-side session context. The vulnerability requires only network access and low privileges, with no user interaction needed to succeed.
Root Cause
The root cause is missing server-side authorization enforcement on object identifiers passed by the client. The plugin trusts request-supplied keys as an authorization signal instead of cross-checking them against the authenticated session. This pattern is a textbook Insecure Direct Object Reference weakness.
Attack Vector
An attacker registers or uses an existing low-privilege WordPress account. The attacker then issues a crafted request to an Avatar plugin endpoint, substituting the identifier of a target user's resource. The plugin processes the action against the target object, producing an integrity impact on data the attacker should not control. See the Patchstack advisory for additional technical detail.
Detection Methods for CVE-2025-39434
Indicators of Compromise
- Unexpected changes to user avatar records or metadata not initiated by the account owner.
- Authenticated HTTP requests to Avatar plugin endpoints containing identifiers that do not match the requesting user's account.
- Bursts of sequential or enumerated identifier values in plugin request parameters.
Detection Strategies
- Review web server and WordPress access logs for authenticated requests targeting Avatar plugin endpoints with mismatched user identifiers.
- Correlate the acting session's user ID against the object identifier in request payloads to surface authorization mismatches.
- Deploy a web application firewall rule to flag parameter tampering patterns against plugin routes.
Monitoring Recommendations
- Enable WordPress audit logging for user profile and avatar modification events.
- Alert on repeated failed or anomalous plugin API calls originating from newly registered accounts.
- Track version inventory of installed WordPress plugins to identify hosts still running Avatar 0.1.4 or earlier.
How to Mitigate CVE-2025-39434
Immediate Actions Required
- Deactivate the Scott Taylor Avatar plugin on any WordPress site running version 0.1.4 or earlier until a fixed release is available.
- Restrict new user registration or elevate the minimum role required to interact with plugin functionality.
- Audit avatar records and user metadata for unauthorized modifications.
Patch Information
At the time of the latest NVD update, no vendor-supplied fixed version is listed for the Scott Taylor Avatar plugin. Administrators should monitor the Patchstack advisory and the plugin repository for an updated release addressing CVE-2025-39434.
Workarounds
- Remove the Avatar plugin and replace it with an actively maintained avatar solution.
- Apply web application firewall rules that block requests where the request-supplied user identifier does not match the authenticated session.
- Limit access to plugin endpoints through server-level access controls until a patch is released.
# Example: disable the vulnerable plugin via WP-CLI
wp plugin deactivate avatar
wp plugin delete avatar
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.