LightRAG: Stored Cross-Site Scripting (XSS) in the LightRAG WebUI chat/answer renderer via ingested content (CVE-2026-86062) | HOL Guard CVE

Medium · CVSS 6.1CVE-2026-86062

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

Answer in brief

CVE-2026-86062 records a Medium severity (CVSS 6.1) vulnerability in LightRAG: Stored Cross-Site Scripting (XSS) in the LightRAG WebUI chat/answer renderer via ingested content. The current sources do not mark it as known exploited. The current feed maps HKUDS/LightRAG (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 22, 2026Source checked Sep 22, 2026First seen by HOL Sep 22, 2026Material review Sep 22, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps HKUDS/LightRAG (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
HKUDS/LightRAGgeneric	<1.5.5	1.5.5

Recommended response

Check inventory. Check lockfiles and deployed manifests for HKUDS/LightRAG.
Review the reported fix. Update HKUDS/LightRAG to 1.5.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 22, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.