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CVE-2026-100639— SiYuan before v3.8.4 Cross-Site Scripting via Kramdown IAL

Quick assessment

Affected
siyuan-note siyuan
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

思源笔记（SiYuan）v3.8.3 存在安全漏洞。该版本在生成侧栏按钮（gutter-button）标记时，未对 data-subtype 属性进行 HTML 转义处理。相关代码位于 app/src/protyle/gutter/button.ts，并通过 app/src/protyle/gutter/index.ts 中的 innerHTML 赋值操作生成标记。 当用户粘贴以纯文本 Markdown 格式传入的、包含 Kramdown 内联属性列表（IAL）的内容时，共享的 Lute 渲染器会从 text/pl

CVSS 8.8 · High EPSS 0.47% · P38
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I. Basic Information for CVE-2026-100639

Vulnerability Information
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Vulnerability Title
SiYuan before v3.8.4 Cross-Site Scripting via Kramdown IAL
Source: CVE Program / CVE List V5
Vulnerability Description
SiYuan v3.8.3 fails to HTML-escape the data-subtype attribute when generating gutter-button markup (app/src/protyle/gutter/button.ts, assigned via innerHTML in app/src/protyle/gutter/index.ts) from content pasted as plain-text Markdown containing a Kramdown inline attribute list (IAL). Because the shared Lute renderer parses Kramdown IAL from text/plain input, an attacker-supplied Markdown snippet using entity-encoded quotes in data-subtype breaks out of the attribute value when the gutter markup is re-parsed by the browser, injecting additional attributes such as autofocus and onfocus. If a victim pastes the crafted Markdown and the affected gutter control receives focus, the injected handler executes; in the Electron desktop application, where the main BrowserWindow enables Node integration and disables context isolation, this results in JavaScript execution with renderer Node.js privileges (remote code execution). Fixed in v3.8.4.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
siyuan-note siyuan 0 ~ 3.8.4 -

II. Public POCs for CVE-2026-100639

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III. Intelligence Information for CVE-2026-100639

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Vendor Advisories for CVE-2026-100639 (1)

Other References for CVE-2026-100639 (1)

Same Patch Batch · siyuan-note · 2026-09-26 · 14 CVEs total

CVE-2026-100646 8.1 HIGH SiYuan before v3.8.4 Authentication Bypass via Missing Origin Header
CVE-2026-100645 8.0 HIGH SiYuan 3.7.0 before 3.8.4 Stored XSS via Gallery Kanban
CVE-2026-100643 8.0 HIGH SiYuan before v3.8.4 Stored XSS via Attribute View textarea
CVE-2026-100641 8.0 HIGH SiYuan before v3.8.4 Stored XSS via Unescaped Flashcard Content
CVE-2026-100642 7.6 HIGH SiYuan v2.1.0 before v3.8.4 Cross-Site Request Forgery via CheckAuth
CVE-2026-100637 7.6 HIGH SiYuan before v3.8.4 Path Traversal via checkoutRepo sessionID
CVE-2026-100638 7.6 HIGH SiYuan before v3.8.4 Path Traversal via setNotebookIcon
CVE-2026-100636 7.6 HIGH SiYuan before v3.8.4 Path Traversal via exportBrowserHTML folder
CVE-2026-100644 7.5 HIGH SiYuan before v3.8.4 SQL Injection via dailyNoteSavePath
CVE-2026-100633 6.5 MEDIUM SiYuan 3.8.0 through 3.8.3 Path Traversal via MCP File Operations
CVE-2026-100635 5.9 MEDIUM SiYuan before v3.8.4 Authentication Bypass via Plaintext Session Cookie
CVE-2026-100634 4.7 MEDIUM SiYuan before v3.8.4 Missing Authorization via siyuan-send-windows
CVE-2026-100640 4.7 MEDIUM SiYuan before v3.8.4 Clipboard Data Disclosure via IPC

IV. Related Vulnerabilities

Same product: siyuan
Same vendor: siyuan-note
Same weakness: CWE-79

V. Comments for CVE-2026-100639

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