CVE-2026-54067 SiYuan: Stored XSS to RCE via CSS-snippet <style> breakout in renderSnippet()
Stored XSS in SiYuan allows remote code execution on Electron desktops via CSS snippet injection, bypassing JavaScript security settings.
- 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-2026-54067?
CVE-2026-54067 is a critical cross-site scripting vulnerability in siyuan-note siyuan, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing </style> breaks out of its surrounding <style> tag when renderSnippet() interpolates it via insertAdjacentHTML. A payload like runs arbitrary JavaScript in the renderer. On Electron desktop builds the renderer runs with nodeIntegration:true, so require('child_process') is reachable from the injected handler and the XSS chains to host RCE. Snippets sync via the workspace repository, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that pulls. The bug also bypasses the user's enabledCSS / enabledJS separation. A user who turned enabledJS off was making a deliberate call not to run untrusted JavaScript; the CSS path runs it anyway. This vulnerability is fixed in 3.7.0.
Which versions are affected by CVE-2026-54067?
3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel.
| Package | Affected | Fixed in |
|---|---|---|
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260628153353-2d5d72223df4 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260628153353-2d5d72223df4 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260628153353-2d5d72223df4 |
How do I fix CVE-2026-54067?
Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260628153353-2d5d72223df4 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-2026-54067 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54067 exists.
Sources
Also known as GHSA-mvjr-vv3c-w4qv, GO-2026-5963.