The SmartEmailing.cz WordPress plugin (marekzak01 SmartEmailing) versions up to 2.2.0 contain a reflected cross-site scripting vulnerability via the 'se-lists-updated' parameter. This vulnerability is due to improper neutralization of input during web page generation, specifically insufficient sanitization and escaping of user-supplied input. An unauthenticated attacker can exploit this by crafting a URL that injects malicious scripts, which execute when a user clicks the link. The vulnerability has a CVSS 3.1 score of 6.1, indicating a medium severity impact with low complexity and no privileges required but requiring user interaction. There is no indication of known exploits in the wild or available patches at this time.

Successful exploitation allows an attacker to execute arbitrary scripts in the context of the affected website for users who click on a malicious link. This can lead to limited confidentiality and integrity impacts such as theft of user session data or manipulation of displayed content. There is no direct impact on availability. The vulnerability requires user interaction and no privileges, increasing its risk in phishing or social engineering scenarios.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should avoid clicking suspicious links involving the 'se-lists-updated' parameter in SmartEmailing plugin pages. Monitoring vendor channels for updates and applying any forthcoming patches promptly is recommended.