CVE-2026-66584 describes an unauthenticated Cross Site Scripting (XSS) vulnerability in the 12 Step Meeting List software affecting all versions up to and including 3.19.16. The vulnerability allows attackers to execute arbitrary scripts in the context of the victim's browser without requiring authentication. The CVSS 3.1 vector indicates network attack vector, low attack complexity, no privileges required, user interaction required, and scope changed, with impacts on confidentiality, integrity, and availability rated as low to low to low respectively.

Successful exploitation could allow an attacker to execute arbitrary scripts in the context of users visiting the affected application, potentially leading to information disclosure, session hijacking, or other client-side impacts. The vulnerability affects confidentiality, integrity, and availability at a low level but is rated high severity due to ease of exploitation and unauthenticated access.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Until a patch is available, users should consider applying any recommended workarounds or input sanitization measures if provided by the vendor.