CVE-2026-15402 is a stored cross-site scripting vulnerability in the Eventin – Event Calendar, Tickets, Registration, Booking & WooCommerce WordPress plugin. The flaw exists in all versions up to and including 4.1.23, specifically in the 'etn_shedule_objective' schedule_slot parameter. Authenticated attackers with contributor-level privileges or above can inject arbitrary web scripts due to improper neutralization of input during web page generation. These scripts execute in the context of users visiting the injected pages, potentially leading to session hijacking or other script-based attacks.

An attacker with contributor-level access or higher can inject persistent malicious scripts that execute in the browsers of users viewing the affected pages. This can lead to information disclosure, session hijacking, or other client-side impacts. The vulnerability does not affect availability and requires authentication with low privileges.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict contributor-level access to trusted users only and consider disabling or limiting use of the vulnerable parameter if possible.