---
id: CVE-2026-93923
title: >-
  SiYuan through 3.8.4 fails to escape heading style attributes when rendering
  outline and bookmark dock HTML, allowing stored cross-site scripting
summary: >-
  SiYuan through 3.8.4 fails to escape heading style attributes when rendering
  outline and bookmark dock HTML, allowing stored cross-site scripting.
  Attackers can supply crafted notebooks or call administrative endpoints to
  inject maliciou…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-79
vendor: siyuan-note
product: github.com/siyuan-note/siyuan/kernel
affected:
  - github.com/siyuan-note/siyuan/kernel <= 3.8.4
published: '2026-09-19'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T16:17:28.387'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93923'
references:
  - url: 'https://github.com/siyuan-note/siyuan'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts#L133
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts#L194
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/model/render.go#L71-L76
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-928g-4hfq-qwvx
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/siyuan-through-3.8.4-stored-xss-via-heading-style-attribute
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-928g-4hfq-qwvx
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-21T15:38:34.747243Z'
epss: 0.00415
epssPercentile: 0.3534
ingestedAt: '2026-09-18T23:54:36.626Z'
---

## Overview

SiYuan through 3.8.4 fails to escape heading style attributes when rendering outline and bookmark dock HTML, allowing stored cross-site scripting. Attackers can supply crafted notebooks or call administrative endpoints to inject malicious style values that execute in the Electron renderer with full system access.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.