AnythingLLM vulnerable to stored DOM XSS in chart caption renderer - LLM-driven prompt injection produces executable HTML via unsanitized renderMarkdown(content.caption) in Chartable component

AnythingLLM is an application that turns pieces of content into context that any LLM can use as references during chatting. Prior to version 1.12.1, AnythingLLM's in-chat markdown renderer has an unsafe custom rule for images that interpolates the markdown image's alt text into an HTML alt="..." attribute without any HTML encoding. Every call-site in the app wraps renderMarkdown(...) with DOMPurify.sanitize(...) as defense-in-depth — except the Chartable component, which renders chart captions with no sanitization. The chart caption is the natural-language text the LLM emits around a create-chart tool call, so any attacker who can influence the LLM's output — most cheaply via indirect prompt injection in a shared workspace document, or directly if they can create a chart record in a multi-user workspace — can trigger stored DOM-level XSS in every other user's browser when they open that conversation. AnythingLLM chat history is loaded server-side via GET /api/workspace/:slug/chats and rendered directly into the chat UI. Version 1.12.1 contains a patch for this issue.