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[ CVE-2026-86062 · Published 22 Sep 2026 ]

lightrag-hku: Stored Cross-Site Scripting (XSS) in the LightRAG WebUI chat/answer renderer via ingested content

CVSS 6.1 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

LightRAG provides simple and fast retrieval-augmented generation. Prior to 1.5.5, lightrag_webui/src/components/retrieval/ChatMessage.tsx renders answer and thinking content with react-markdown, rehypeRaw, and skipHtml=false without an HTML sanitizer. An attacker who can add a document can store raw HTML that is returned through the query path and rendered as active content by MessageMarkdown. A user who later retrieves the content can execute attacker-controlled JavaScript through elements such as an iframe srcdoc; the additional Mermaid securityLevel: loose rendering path also injects generated SVG through innerHTML. The script runs in the LightRAG WebUI origin and can read the API token in localStorage and perform API actions as the victim. This issue is fixed in version 1.5.5.

[ Fixes ]Fixes and patches

  • lightrag-hku 1.5.5Fixed version · GitHub Advisories · pip package lightrag-hku: upgrade to 1.5.5 or later (affected <= 1.5.4)

[ Packages ]Affected open-source packages

[ References ]References