CVE-2026-116168: SiYuan before v3.8.7 Path Traversal Local File Read via MCP Asset Tool

Severity: medium (CVSS 6.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-25 · updated 2026-10-25
Weakness: CWE-22

Description

SiYuan before 3.8.7 contains a path traversal vulnerability in the MCP asset tool because validateAssetUploadPaths relies on an incomplete sensitive-path blacklist that omits .env and other secret files. Authenticated attackers driving the MCP asset upload action can copy such local files into the workspace and read them back via /assets/ over HTTP.

Affected products

siyuan-note siyuan: 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-q768-4j87-gf3w
https://www.vulncheck.com/advisories/siyuan-before-3.8.7-path-traversal-local-file-read-via-mcp-asset-tool

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