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CVE-2026-100640— SiYuan before v3.8.4 Clipboard Data Disclosure via IPC

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.

在 SiYuan 3.8.4 版本之前，siyuan-get IPC 处理器中存在一个权限验证遗漏漏洞，该漏洞允许远程内核渲染器通过调用与明文内容匹配的 clipboardReadMathML、clipboardReadOffice 和 clipboardReadWPS 命令，从而访问本地剪贴板的原生数据格式。攻击者若控制了远程渲染器的内容，便可以在用户操作剪贴板粘贴的过程中，获取到本地的 MathML 公式、Office 文件字节数据以及 WPS 文件字节数据。

CVSS 4.7 · Medium EPSS 0.19% · P8

Possible ATT&CK Techniques 1 AI

T1115 · Clipboard Data
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I. Basic Information for CVE-2026-100640

Vulnerability Information
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Vulnerability Title
SiYuan before v3.8.4 Clipboard Data Disclosure via IPC
Source: CVE Program / CVE List V5
Vulnerability Description
SiYuan before v3.8.4 contains an authorization omission in the siyuan-get IPC handler that allows remote-kernel renderers to access native clipboard formats by invoking clipboardReadMathML, clipboardReadOffice, and clipboardReadWPS commands with matching plaintext. Attackers controlling remote renderer content can obtain MathML formulas, Office bytes, and WPS bytes from local clipboard during user-mediated paste operations.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
信息暴露
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-2026-100640

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III. Intelligence Information for CVE-2026-100640

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Vendor Advisories for CVE-2026-100640 (1)

Other References for CVE-2026-100640 (1)

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

CVE-2026-100639 8.8 HIGH SiYuan before v3.8.4 Cross-Site Scripting via Kramdown IAL
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

IV. Related Vulnerabilities

Same product: siyuan
Same vendor: siyuan-note
Same weakness: CWE-200

V. Comments for CVE-2026-100640

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