EUVD-2026-276788

fkie_cve-2026-33066

SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the backend renderREADME function uses lute.New() without calling SetSanitize(true), allowing raw HTML embedded in Markdown to pass through unmodified. The frontend then assigns the rendered HTML to innerHTML without any additional sanitization. A malicious package author can embed arbitrary JavaScript in their README that executes when a user clicks to view the package details. Because SiYuan's Electron configuration enables nodeIntegration: true with contextIsolation: false, this XSS escalates directly to full Remote Code Execution. The issue was patched in version 3.6.1.

GHSA-4663-4mpg-879v — SiYuan has Stored XSS to RCE via Unsanitized Bazaar README Rendering

Affected: Go: github.com/siyuan-note/siyuan/kernel

# Stored XSS to RCE via Unsanitized Bazaar README Rendering

## Summary

SiYuan's Bazaar (community marketplace) renders package README content without HTML sanitization. The backend `renderREADME` function uses `lute.New()` without calling `SetSanitize(true)`, allowing raw HTML embedded in Markdown to pass through unmodified. The frontend then assigns the rendered HTML to `innerHTML` without any additional sanitization. A malicious package author can embed arbitrary JavaScript in their README that executes when a user clicks to view the package details. Because SiYuan's Electron configuration enables `nodeIntegration: true` with `contextIsolation: false`, this XSS escalates directly to full Remote Code Execution.

## Affected Component

- **README rendering (backend)**: `kernel/bazaar/package.go:635-645` (`renderREADME` function) - **README rendering (frontend)**: `app/src/config/bazaar.ts:607` (`innerHTML` assignment) - **Electron config**: `app/electron/main.js:422-426` (`nodeIntegration: true`, `contextIsolation: false`)

## Affected Versions

- SiYuan <= 3.5.9 - ## Severity

**Critical** — CVSS 9.6 (AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H)

- CWE-79: Improper Neutralization of Input During Web Page Generation (Stored XSS)

Note: This vector requires one click (user viewing the package README), unlike the metadata vector which is zero-click.

## Vulnerable Code

### Backend: `kernel/bazaar/package.go:635-645`

```go func renderREADME(repoURL string, mdData []byte) (ret stri…

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EUVD-2026-276788

fkie_cve-2026-33066

GHSA-4663-4mpg-879v — SiYuan has Stored XSS to RCE via Unsanitized Bazaar README Rendering