---
title: "CVE-2026-54067: SiYuan: Stored XSS to RCE via CSS-snippet <style> breakout in renderSnippet()"
url: https://erroneo.us/security/cve/CVE-2026-54067/
description: "CVE-2026-54067 (github.com/siyuan-note/siyuan/kernel (Go)): SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-24
date_modified: 2026-07-10
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-54067"
kev: false
cvss: 9.9
epss: 0.00541
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 45: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 45% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes github.com/siyuan-note/siyuan/kernel (Go) < 0.0.0-20260628153353-2d5d72223df4, fixed in 0.0.0-20260628153353-2d5d72223df4 . Check your lockfile, including transitive dependencies.

## What it is

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing breaks out of its surrounding 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('childprocess') 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

- Go `github.com/siyuan-note/siyuan/kernel` < 0.0.0-20260628153353-2d5d72223df4 → fixed: 0.0.0-20260628153353-2d5d72223df4

## Affected products (CVE record)

- siyuan-note siyuan: < 3.7.0

## Severity

- GitHub_M CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.54% probability of exploitation activity in the next 30 days; percentile 45.

## Sources

- [GitHub Advisory GHSA-mvjr-vv3c-w4qv](https://github.com/advisories/GHSA-mvjr-vv3c-w4qv)
- [CVE.org record CVE-2026-54067](https://www.cve.org/CVERecord?id=CVE-2026-54067)
- [NVD entry CVE-2026-54067](https://nvd.nist.gov/vuln/detail/CVE-2026-54067)
- [github.com](https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mvjr-vv3c-w4qv)

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Source page: https://erroneo.us/security/cve/CVE-2026-54067/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt