Critical SQL Injection Vulnerability in Rustaurius Ultimate WP Mail Plugin (CVE-2025-47490)

A high-severity SQL injection vulnerability (CVE-2025-47490) has been identified in the Rustaurius Ultimate WP Mail plugin, affecting versions up to and including 1.3.4. The flaw, rated 8.5 (HIGH) on the CVSS scale, allows unauthenticated attackers to execute arbitrary SQL commands via malformed input¹. This vulnerability poses a significant risk to websites using the plugin, particularly those handling sensitive data through email functionalities.

Technical Overview

The vulnerability stems from improper neutralization of special elements in SQL queries, a common issue in plugins that directly concatenate user input into database commands². While the exact attack vector hasn’t been publicly disclosed, researchers at VulDB confirm the flaw enables unauthenticated SQL injection, meaning attackers don’t need valid credentials to exploit it¹.

Affected systems include all WordPress installations running Ultimate WP Mail version 1.3.4 or earlier. The plugin’s popularity in e-commerce and membership sites increases the potential impact, as these often store sensitive user data in databases accessible through vulnerable queries.

Mitigation and Patching

The primary mitigation is immediate updating to the latest patched version of the plugin. Site administrators should:

Check the plugin version in WordPress admin dashboard
Update to the newest release if available
Monitor for suspicious database activity

For organizations unable to immediately update, temporary measures include restricting database user permissions and implementing web application firewall rules to block suspicious SQL patterns³. Sucuri’s April 2025 vulnerability roundup recommends virtual patching through WAF solutions as an interim protection⁴.

Broader Context

This vulnerability appears in a broader trend of WordPress plugin security issues. The same plugin has another documented vulnerability (CVE-2025-32694) involving URL redirection risks⁵. Recent months have seen multiple critical flaws in popular plugins like Ultimate Member (CVE-2025-0308) and Kadence WooCommerce Email Designer (CVE-2025-39557)⁴.

The NVD database shows a 27% increase in WordPress-related CVEs in Q1 2025 compared to the same period last year, with SQL injection remaining the most common attack vector⁶. This highlights the ongoing challenges in securing third-party WordPress extensions.

Detection and Response

Organizations should review server logs for unusual database queries, particularly those containing SQL keywords like UNION, SELECT, or DROP. Monitoring tools should be configured to alert on multiple failed login attempts or unexpected database modifications.

For incident responders, the Wordfence weekly report suggests specific SQL patterns to watch for in this case, though exact signatures haven’t been made public to prevent active exploitation⁷. Network defenders should prioritize reviewing any systems using this plugin, especially those processing sensitive information through email functions.

Conclusion

CVE-2025-47490 represents a serious threat to WordPress sites using the affected plugin. Immediate action is required to either update or mitigate the vulnerability. The incident underscores the importance of regular plugin maintenance and monitoring in WordPress environments.

As new details emerge, organizations should consult the NVD entry and plugin developer communications for additional guidance. This case serves as another reminder of the persistent risks associated with third-party WordPress extensions and the need for robust security practices around their use.