This vulnerability involves an authenticated stored XSS in Feehi CMS v2.1.1, where attackers can inject malicious scripts or HTML via the Page Sign parameter. The flaw requires authentication, meaning the attacker must have valid access to the CMS to exploit it. The vulnerability could lead to script execution in users' browsers when they access the affected content. No official remediation or patch information is provided in the available data.

Successful exploitation allows an authenticated attacker to execute arbitrary scripts in the context of other users viewing the injected content, potentially leading to session hijacking, defacement, or other client-side attacks. Since exploitation requires authentication, the impact is limited to users with access to the CMS environment.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict access to trusted users only and consider reviewing and sanitizing inputs related to the Page Sign parameter to mitigate injection risks.