GHSA-w95v-4h65-j455: github.com/siyuan-note/siyuan/kernel (CVE-2026-40107)

SiYuan Affected by Zero-Click NTLM Hash Theft and Blind SSRF via Mermaid Diagram Rendering

CVSS 8.7 HighEPSS 0.0032 · 25th percentile

Published by the GitHub Advisory Database at 10 Apr 2026, 19:21 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
github.com/siyuan-note/siyuan/kernel	Go	<0.0.0-20260407035653-2f416e5253f1	0.0.0-20260407035653-2f416e5253f1

Identifiers

GHSA-w95v-4h65-j455 · CVE-2026-40107 · GO-2026-5702

Weakness (CWE)

CWE-918

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

SiYuan (github.com/siyuan-note/siyuan/kernel) versions before 0.0.0-20260407035653-2f416e5253f1 are affected. A victim who opens a note containing a malicious Mermaid diagram causes the Electron client to fetch an attacker-controlled image URL, which on Windows can leak NTLMv2 hashes and on all platforms acts as a blind SSRF and tracking request. Upgrade to 0.0.0-20260407035653-2f416e5253f1 or later. The source gives no workaround.

Written 7 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.7	High	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:L/SA:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0032, the 25th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 15:06 UTC First seen by agentprime
31 Oct 2026, 15:06 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.