CVE-2026-87813

SiYuan before v3.8.2 Stored XSS via unescaped asset filenames

8.4 High

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in the Search Assets result list where asset filenames are interpolated into HTML without escaping. Authenticated attackers can craft asset filenames containing malicious markup that executes JavaScript in the victim's browser when searching assets, enabling same-origin API requests and application state manipulation.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: Active

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: None

Exploit likelihood

0.37%Up 0.1 points since Sep 10, 2026

What each source reports

CVE List Score used 8.4

SiYuan before v3.8.2 Stored XSS via unescaped asset filenames

Record: CVE-2026-87813
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2026-74839 8.4

Record: EUVD-2026-74839
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-x62c-gcj4-v66g 8.4

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in the Search Assets...

Record: GHSA-x62c-gcj4-v66g
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/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: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Weakness: CWE-79
Updated: 2026-11-02

NVD 8.4

Record: CVE-2026-87813
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/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: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Weakness: CWE-79
Updated: 2026-11-02

OSV 8.4

SiYuan before v3.8.2 Stored XSS via unescaped asset filenames

Record: CVE-2026-87813
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/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-2026-87813 is a high vulnerability (CVSS 8.4) in Siyuan-note Siyuan, published September 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 30th percentile. No source names a fixed version.