This vulnerability (CVE-2026-65438) is an unauthenticated Cross-Site Scripting (XSS) issue in the Message Filter for Contact Form 7 plugin, affecting versions up to 1.6.3.9. It is caused by improper neutralization of input during web page generation (CWE-79). The CVSS 3.1 base score is 7.1, reflecting network attack vector, low attack complexity, no privileges required, user interaction required, and impacts on confidentiality, integrity, and availability with scope changed. No patch or official remediation level has been published as of the data provided.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary scripts in the context of the affected web application without authentication. This can lead to partial compromise of confidentiality, integrity, and availability of the affected system or user data. The vulnerability affects all users of the plugin up to version 1.6.3.9, potentially exposing them to XSS attacks.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should consider disabling or limiting use of the vulnerable plugin version or applying any available temporary mitigations recommended by the vendor. Monitor vendor channels for updates.