CVE-2025-49288: Ultimate WP Mail Auth Bypass Vulnerability

CVE-2025-49288 Overview

CVE-2025-49288 is a missing authorization vulnerability in the Rustaurius Ultimate WP Mail plugin for WordPress. The flaw affects all versions through 1.3.5 and enables authentication bypass through broken access control [CWE-862]. An attacker with low-privilege access can invoke protected plugin functionality without proper authorization checks. The vulnerability has network attack vector characteristics and impacts confidentiality, integrity, and availability of affected WordPress installations.

Critical Impact

Authenticated attackers with minimal privileges can bypass authorization controls in Ultimate WP Mail, potentially leading to unauthorized access to email functionality, data exposure, and site compromise.

Affected Products

• Rustaurius Ultimate WP Mail plugin for WordPress
• Versions from n/a through 1.3.5
• WordPress sites with the ultimate-wp-mail plugin installed

Discovery Timeline

• 2025-06-06 - CVE-2025-49288 published to NVD
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-49288

Vulnerability Analysis

The vulnerability resides in the Ultimate WP Mail plugin, which provides email management functionality for WordPress sites. The plugin fails to enforce proper authorization checks on sensitive operations. This allows authenticated users with low privilege levels to invoke functions reserved for administrators.

The attack requires network access and low-level authentication but no user interaction. Successful exploitation compromises confidentiality, integrity, and availability of the affected WordPress installation. The Exploit Prediction Scoring System (EPSS) places this CVE in the 43rd percentile.

Root Cause

The root cause is a missing authorization check [CWE-862] on one or more plugin endpoints. The plugin registers callable actions or AJAX handlers without verifying that the requesting user holds the required capability. WordPress plugins typically enforce authorization through current_user_can() capability checks or nonce verification via check_ajax_referer(). The Ultimate WP Mail plugin omits these controls on protected handlers through version 1.3.5.

Attack Vector

An attacker authenticated as a low-privilege user, such as a Subscriber, sends crafted HTTP requests to the vulnerable plugin endpoints. Because the plugin does not validate the user's capabilities before executing privileged actions, the attacker gains access to functionality intended for site administrators. Technical details are available in the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-49288

Indicators of Compromise

• Unexpected HTTP POST requests to admin-ajax.php or plugin REST endpoints originating from low-privilege user sessions
• Outbound email activity from the WordPress site that does not correlate with legitimate administrator actions
• Modifications to Ultimate WP Mail configuration or email templates performed by non-administrator accounts

Detection Strategies

• Audit WordPress access logs for requests to ultimate-wp-mail plugin paths from user accounts without administrator roles
• Review the plugin's email send history and compare against expected administrator-initiated activity
• Inspect WordPress user activity logs for privilege-sensitive actions executed by Subscriber or Contributor accounts

Monitoring Recommendations

• Enable WordPress audit logging to capture AJAX and REST API calls to vulnerable plugin endpoints
• Forward WordPress and web server logs to a centralized SIEM for correlation and alerting on anomalous low-privilege activity
• Monitor for new or modified administrator-level configurations performed outside expected change windows

How to Mitigate CVE-2025-49288

Immediate Actions Required

• Identify all WordPress sites running the Ultimate WP Mail plugin at version 1.3.5 or earlier
• Deactivate and remove the plugin until a patched version is available if the plugin is not business-critical
• Restrict user registration and audit existing low-privilege accounts for suspicious activity

Patch Information

At the time of publication, the Patchstack Vulnerability Report lists all versions through 1.3.5 as affected. Administrators should monitor the plugin's WordPress.org page and the vendor advisory for a fixed release and upgrade immediately when available.

Workarounds

• Apply a virtual patch through a Web Application Firewall (WAF) to block unauthenticated or low-privilege access to vulnerable plugin endpoints
• Disable the Ultimate WP Mail plugin until an official patch is released
• Enforce the principle of least privilege by removing unused low-privilege accounts and disabling open user registration

# Disable the plugin via WP-CLI until a patch is available
wp plugin deactivate ultimate-wp-mail
wp plugin delete ultimate-wp-mail

# Verify no residual plugin files remain
ls -la wp-content/plugins/ | grep ultimate-wp-mail