CVE-2024-9204 is a reflected cross-site scripting vulnerability in the nerdpressteam Smart Custom 404 Error Page WordPress plugin. The flaw is due to insufficient input sanitization and output escaping of the $_SERVER['REQUEST_URI'] variable, which is used during web page generation. This allows unauthenticated attackers to inject malicious scripts that execute when a user visits a crafted URL. The vulnerability affects all versions up to and including 11.4.7. The CVSS 3.1 base score is 6.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N), reflecting network attack vector, low attack complexity, no privileges required, user interaction required, scope changed, and low impact on confidentiality and integrity with no impact on availability.

Successful exploitation can lead to execution of arbitrary scripts in the context of the affected website, potentially allowing attackers to steal user credentials, perform actions on behalf of users, or conduct other malicious activities within the user's browser session. The impact is limited to confidentiality and integrity with no direct availability impact. No known exploits are reported in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should consider disabling the plugin or implementing web application firewall (WAF) rules to block malicious payloads targeting the $_SERVER['REQUEST_URI'] parameter. Avoid clicking on suspicious links that may exploit this vulnerability.