CVE-2026-66395 | SiYuan desktop before v3.7.2 contains a reflected cross-site… | CVSS 9.6 CRITICAL

Description

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.

Metadata

CVE ID: CVE-2026-66395
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-07-26 12:22 UTC
Published: 2026-07-27 15:43 UTC
Last updated: 2026-07-28 01:06 UTC
Primary CWE: CWE-79
Improper Neutralization of Input During Web Page Generation …
Vendor / Product: siyuan-note / siyuan
Sources: cve.org · NVD

Severity & Metrics

9.6 CRITICAL CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: no
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
siyuan-note	siyuan	—	0 < 3.7.2, 3.7.2

Weakness (CWE)

CWE	Source	Description
CWE-79	cna	Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS scores (2)

Score	Severity	Version	Source	Vector
9.6	CRITICAL	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
9.4	CRITICAL	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

References (2)

GitHub Security Advisory (GHSA-6gx2-8gcr-x83f) https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6gx2-8gcr-x83f
VulnCheck Advisory: SiYuan Desktop before v3.7.2 Reflected XSS to RCE via siyuan Protocol https://www.vulncheck.com/advisories/siyuan-desktop-before-reflected-xss-to-rce-via-siyuan-protocol