The Tag plugin for GLPI 11 before version 2.14.4 improperly neutralizes input during web page generation, specifically in the PluginTagTag::preKanbanContent() function. It stores tag names without sanitizing HTML and renders them directly into the Kanban badge markup without escaping output. This results in a stored cross-site scripting vulnerability exploitable by authenticated users with tag management create or update rights. The malicious script executes in the context of any user who views the Kanban view of an item tagged with the crafted tag name.

An attacker with authenticated access and tag management privileges can inject malicious HTML/JavaScript into tag names. This code executes in the browsers of other users viewing the Kanban view, potentially leading to session hijacking, credential theft, or other malicious actions within the GLPI application context. The vulnerability affects confidentiality, integrity, and availability of user sessions and data accessible via the GLPI interface.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict tag management create or update rights to trusted users only to reduce risk. Monitor vendor channels for updates and apply any released patches promptly.