Sensitive-Path Guard Bypass in SiYuan Personal Knowledge Management System
CVE-2026-100633

8.5HIGH

Key Information:

Vendor

Siyuan-note

Status
Siyuan
Vendor
CVE Published:
26 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-100633?

SiYuan, a self-hosted personal knowledge management system, has a vulnerability in versions 3.8.0 through 3.8.3 that affects the sensitive-path guard due to an incomplete fix. The MCP file tool allows an authenticated administrator to bypass the protected-workspace-file denylist during recursive operations. This flaw can permit exposure of sensitive files, enabling commands like file.grep, file.copy, and unzip to interact with protected pathways without adequate safeguarding. The issue has been addressed in version 3.8.4.

Affected Version(s)

siyuan 3.8.0 < 3.8.4

siyuan 3.8.4

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-100633
Created by dpfkdlemtp

References

https://github.com/siyuan-note/siyuan/security/advisories...
vendor-advisory
https://www.vulncheck.com/advisories/siyuan-3.8.0-through...
third-party-advisory

CVSS V4

Score:
8.5
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

dpfkdlemtp
.