CVE-2026-66629 is an improper neutralization of input during web page generation (CWE-79) vulnerability in Themeum Kirki, allowing unauthenticated attackers to perform cross-site scripting (XSS) attacks. The vulnerability affects Kirki versions up to and including 6.2.3. The CVSS 3.1 base score is 7.1, indicating a high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and impacts on confidentiality, integrity, and availability. No vendor advisory or patch information is currently available.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary scripts in the context of the affected web application, potentially leading to information disclosure, modification of data, or disruption of service. Since the vulnerability is unauthenticated and remotely exploitable, it poses a significant risk to affected systems.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider applying temporary mitigations such as input validation or output encoding if feasible, and monitor for updates from Themeum regarding patches.