CVE-2026-33066 SiYuan has Stored XSS to RCE via Unsanitized Bazaar README Rendering
A stored XSS vulnerability in SiYuan allows malicious package authors to execute arbitrary code via unsanitized README rendering in the Electron app.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33066?
CVE-2026-33066 is a medium-severity cross-site scripting vulnerability in B3log Siyuan, published on 20 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-33066?
3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260314111550-b382f50e1880 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260314111550-b382f50e1880 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260314111550-b382f50e1880 |
Products include B3log Siyuan.
How do I fix CVE-2026-33066?
Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260314111550-b382f50e1880 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-2026-33066 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33066 exists.
Other vulnerabilities in B3log Siyuan
- CVE-2026-32938 SiYuan has an Arbitrary File Read in its Desktop Publish Service
- CVE-2026-33669 SiYuan has Arbitrary Document Reading within the Publishing Service
- CVE-2026-33670 SiYuan has directory traversal within its publishing service
- CVE-2026-32767 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API
- CVE-2024-53504 SQL injection in n/a
Sources
Also known as GHSA-4663-4mpg-879v, GO-2026-4743.