What’s Vulnerable › Vulnerabilities

CVE-2026-116171: SiYuan 3.5.4 before 3.8.7 Sensitive Path Bypass via Windows Extended-Length Prefix

• Severity: medium (CVSS 4.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-25 · updated 2026-10-28
• Weakness: CWE-22

Description

SiYuan 3.5.4 before 3.8.7 on Windows contains a sensitive-path denylist bypass in IsSensitivePath because the Windows extended-length prefix (\\?\) survives filepath.Clean and matches no forbidden prefix. Authenticated API callers can prepend the prefix to localPath in /api/import/importStdMd to copy workspace conf files, including the API token and TLS private keys, into assets served to unauthenticated clients.

Affected products

• siyuan-note siyuan: from 3.5.4 before 3.8.7 — fixed in 3.8.7

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.8.7. Check the vendor advisory for mitigations.

References

• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6gmc-424x-xgpm
• https://www.vulncheck.com/advisories/siyuan-3.5.4-before-3.8.7-sensitive-path-bypass-via-windows-extended-length-prefix

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