CVE-2026-105454

RT's automatic link creation for URLs in HTML ticket content does not HTML-escape the URL it places in the link. A URL crafted to break out of the link's address can add a script that runs when the ticket history is displayed, with no further action by the viewer. Anyone who can add HTML content to a ticket can plant it. That includes an unauthenticated sender of HTML email to any queue that grants CreateTicket or ReplyToTicket to Everyone, which is routine for a queue that accepts mail from the public. The script runs in the session of any user who views the ticket, and can act in RT with that user's authority. This issue was fixed in version 5.0.11 and 6.0.4