A stored cross-site scripting (XSS) vulnerability exists in the "POST /api/prompts/share" endpoint of parisneo/lollms (latest version). The endpoint stores attacker-controlled "prompt_content" into "DBDirectMessage.content" without server-side sanitization. When a victim opens the direct message (DM) thread, the message is rendered by the DM UI through "MessageContentRenderer", which uses "v-html" to insert rendered HTML into the DOM. The frontend sanitizer, which is regex-based, fails to comprehensively sanitize attacker-controlled HTML, allowing malicious payloads to execute in the victim's browser context. This vulnerability enables any authenticated user to send a malicious prompt-share message to another user's inbox, leading to arbitrary JavaScript execution, authenticated actions as the victim, exposure of same-origin application data, and potential account takeover.