Vulnerability · Published Jun 24, 2026 · Assigned by GitHub_M

CVE-2026-54067SiYuan: Stored XSS to RCE via CSS-snippet <style> breakout in renderSnippet()

Critical 9.9

In plain English

A critical-severity cross-site scripting in siyuan from siyuan-note. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.9Critical

Exploit odds (30 days)0.4%top 67.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/siyuan-note/siyuan/kernel	0.0.0-20260628153353-2d5d72223df4	GO-2026-5963
Go	github.com/siyuan-note/siyuan/kernel	0.0.0-20260628153353-2d5d72223df4	GHSA-mvjr-vv3c-w4qv

Affected products (as reported)

Vendor	Product	Versions
siyuan-note	siyuan	< 3.7.0

Weakness: CWE-79, CWE-1188 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mvjr-vv3c-w4qv x_refsource_CONFIRM