The zinoui HTTP Headers plugin for WordPress suffers from a stored cross-site scripting vulnerability (CWE-79) due to improper neutralization of input during web page generation. Authenticated users with administrator-level permissions can inject arbitrary scripts via the plugin's admin settings. This vulnerability impacts multi-site WordPress setups or installations where unfiltered_html is disabled, allowing persistent script injection that executes when affected pages are viewed. The CVSS 3.1 base score is 4.4, reflecting a medium severity with network attack vector, high attack complexity, and required privileges. No vendor-provided patch or remediation is currently documented.

Successful exploitation allows authenticated administrators to inject malicious scripts that execute in the context of users viewing the affected pages. This can lead to limited confidentiality and integrity impacts, such as session hijacking or unauthorized actions performed by users. The vulnerability does not affect availability. The impact is constrained by the requirement for administrator privileges and specific WordPress configurations (multi-site or unfiltered_html disabled). No known active exploitation has been reported.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, limit administrator access to trusted users only and consider disabling or removing the zinoui HTTP Headers plugin in affected environments, especially multi-site installations or those with unfiltered_html disabled. Monitor vendor channels for updates or patches addressing this vulnerability.