CVE Alert: CVE-2025-11920 – whyun – WPCOM Member

Risk verdict

High. Exploitation is possible by authenticated users with contributor-level access, potentially enabling remote code execution; patching should be treated as urgent.

Why this matters

If exploited, the attacker can execute PHP on the server, bypassing some access controls and exposing or altering data, compromising site integrity. The impact spans data loss, downtime, and reputational damage, with possible persistence or broader access within the hosting environment.

Most likely attack path

An authenticated attacker (Contributor+) uses the vulnerable shortcode’s action parameter to trigger a local file inclusion, loading arbitrary PHP. No user interaction beyond the existing login is required; once code runs, sensitive data may be read or modified and a backdoor could be installed, potentially enabling lateral movement within the web server environment.

Who is most exposed

WordPress sites running the WPCOM Member plugin, especially where contributors can insert shortcodes and PHP execution is possible from included files (common in shared or managed WordPress hosting with flexible plugin usage).

Detection ideas

• Monitor shortcode processing for action parameters that attempt to include PHP files.
• Look for PHP include/require errors originating from plugin paths.
• Detect sudden creation or execution of PHP files under wp-content.
• Alert on spikes in 500 errors after shortcode rendering.
• Review access logs for requests exploiting shortcode-based inclusion patterns.

Mitigation and prioritisation

• Patch to the fixed release or temporarily disable the plugin; implement change control.
• Enforce least privilege for Contributor+ accounts and restrict shortcode capabilities.
• Deploy WAF/IPS rules to block LFI-like patterns; harden PHP execution controls.
• Tighten file permissions and upload restrictions; disable arbitrary PHP uploads.
• Ensure backups, incident response readiness, and post-patch validation.