CVE-2026-4871 is a stored cross-site scripting vulnerability in the Sports Club Management WordPress plugin by pstruik. It affects all versions up to and including 1.12.9. The vulnerability exists because the plugin does not properly sanitize or escape user input in the 'before' and 'after' attributes of the scm_member_data shortcode. This allows authenticated users with Contributor-level privileges or higher to inject arbitrary JavaScript code that executes in the context of other users viewing the injected content. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting network attack vector, low attack complexity, required privileges, no user interaction, and partial impact on confidentiality and integrity.

An attacker with Contributor-level or higher access can inject persistent malicious scripts into pages via the vulnerable shortcode attributes. These scripts execute in the browsers of users who view the affected pages, potentially leading to unauthorized actions or data disclosure limited to the scope of the injected script. The vulnerability does not impact availability. There are no reported exploits in the wild, and the impact is limited by the requirement for authenticated access.

No official patch or remediation is currently available from the vendor. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is released, restrict Contributor-level and higher access to trusted users only and consider disabling or limiting use of the scm_member_data shortcode attributes 'before' and 'after' if possible. Monitor vendor channels for updates and apply patches promptly once available.