The Passster plugin for WordPress suffers from a stored cross-site scripting vulnerability (CWE-79) in its 'content_protector' shortcode. This allows authenticated attackers with Contributor-level permissions or higher to inject arbitrary web scripts into pages. These scripts execute in the context of users who access the compromised pages, potentially leading to session hijacking or other script-based attacks. Although a partial fix was applied in version 4.2.21, versions up to 4.2.24 remain vulnerable. The CVSS 3.1 base score is 6.4, reflecting network attack vector, low attack complexity, and privileges required at the contributor level. No vendor advisory or patch links are provided, so the full remediation status is unclear.

An attacker with Contributor-level access can inject persistent malicious scripts into pages protected by the plugin. These scripts execute in the browsers of users who view the affected pages, potentially compromising user sessions or performing unauthorized actions within the context of the victim's browser. The vulnerability does not affect availability but impacts confidentiality and integrity to a limited extent. There are no known exploits in the wild as per the provided data.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since a partial patch was introduced in version 4.2.21 but the vulnerability persists through 4.2.24, users should monitor for an official full fix from the vendor. Until then, restrict Contributor-level access to trusted users only and consider disabling or removing the Passster plugin if feasible to reduce risk.