CVE-2026-93923

SiYuan through 3.8.4 Stored XSS via Heading Style Attribute

8.6 High

SiYuan through 3.8.4 fails to escape heading style attributes when rendering outline and bookmark dock HTML, allowing stored cross-site scripting. Attackers can supply crafted notebooks or call administrative endpoints to inject malicious style values that execute in the Electron renderer with full system access.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Active

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.60%Up 0.2 points since Sep 19, 2026

What each source reports

CVE List Score used 8.6

SiYuan through 3.8.4 Stored XSS via Heading Style Attribute

Record: CVE-2026-93923
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2026-83459 8.6

Record: EUVD-2026-83459
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-qvp6-cjg5-8753 8.6

SiYuan through 3.8.4 fails to escape heading style attributes when rendering outline and bookmark...

Record: GHSA-qvp6-cjg5-8753
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-79
Updated: 2026-11-02

NVD 8.6

Record: CVE-2026-93923
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-79
Updated: 2026-11-02

OSV 8.6

SiYuan through 3.8.4 Stored XSS via Heading Style Attribute

Record: CVE-2026-93923
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-79
Updated: 2026-11-02

Affected products

siyuan-note siyuan

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-93923 is a high vulnerability (CVSS 8.6) in Siyuan-note Siyuan, published September 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 48th percentile. No source names a fixed version.