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CVE-2026-100642— SiYuan v2.1.0 before v3.8.4 Cross-Site Request Forgery via CheckAuth

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）v2.1.0 至 v3.8.4（不含 v3.8.4）版本中，存在一个跨站请求伪造（CSRF）漏洞。该漏洞位于 CheckAuth 锁屏界面透传分支，允许在未经验证 Origin 头的情况下，将管理员权限授予回环（loopback）请求。 攻击者可构造恶意网页，诱导受害者浏览器发起无凭据的跨源请求，从而强制终止内核进程、读取工作区配置和代理设置，并执行需要管理员权限的操作。

CVSS 7.6 · High EPSS 0.11% · P1
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I. Basic Information for CVE-2026-100642

Vulnerability Information
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Vulnerability Title
SiYuan v2.1.0 before v3.8.4 Cross-Site Request Forgery via CheckAuth
Source: CVE Program / CVE List V5
Vulnerability Description
SiYuan versions from v2.1.0 before v3.8.4 contain a cross-site request forgery vulnerability in the CheckAuth lock-screen pass-through branch that grants administrator access to loopback requests without validating Origin headers. Attackers can craft malicious web pages that force victims to terminate the kernel process, read workspace configuration and proxy settings, and trigger administrative actions via zero-credential cross-origin requests from the victim's browser.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
源验证错误
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
siyuan-note siyuan 2.1.0 ~ 3.8.4 -

II. Public POCs for CVE-2026-100642

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III. Intelligence Information for CVE-2026-100642

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Vendor Advisories for CVE-2026-100642 (1)

Other References for CVE-2026-100642 (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-2026-100637 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-346

V. Comments for CVE-2026-100642

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