CVE-2026-86062 LightRAG: Stored Cross-Site Scripting (XSS) in the LightRAG WebUI chat/answer renderer via ingested content
Attackers can inject malicious scripts via ingested documents in LightRAG WebUI, allowing execution of JavaScript and theft of API tokens from victims.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-86062?
CVE-2026-86062 is a medium-severity cross-site scripting vulnerability in HKUDS LightRAG, published on 22 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-86062?
3 open source packages ship an affected version, including lightrag-hku.
| Package | Affected | Fixed in |
|---|---|---|
lightrag-hku PyPI | All versions | 1.5.5 |
lightrag-hku PyPI | All versions | 1.5.5 |
lightrag-hku PyPI | All versions | 1.5.5 |
How do I fix CVE-2026-86062?
Upgrade lightrag-hku to 1.5.5 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-86062 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86062 exists.
Sources
Also known as GHSA-xpjq-3w4w-w5wr, PYSEC-2026-4065.