The Events Calendar Countdown Addon by CoolHappy versions up to 1.4.9 contain a stored cross-site scripting vulnerability due to improper input neutralization during web page generation. This vulnerability (CVE-2025-49311) allows attackers with at least low privileges and requiring user interaction to inject malicious scripts that can compromise confidentiality, integrity, and availability of affected systems. The CVSS 3.1 vector indicates network attack vector, low attack complexity, required privileges, and user interaction, with a scope change and partial impact on confidentiality, integrity, and availability. No patch or vendor advisory is currently provided, and no exploits are known in the wild.

Successful exploitation of this stored XSS vulnerability can lead to partial compromise of confidentiality, integrity, and availability of the affected system or user data. Attackers could execute arbitrary scripts in the context of the affected web application, potentially leading to session hijacking, data theft, or other malicious actions. However, exploitation requires user interaction and some privileges, limiting the ease of exploitation. There are no reports of active exploitation 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 exercise caution with this addon, restrict privileges where possible, and consider disabling or removing the addon if feasible. Monitor vendor channels for updates or patches addressing this vulnerability.