CVE-2026-87811

HIGH 7.3

SiYuan before v3.8.2 Stored XSS via notebook template paths

CVSS Score

7.3

EPSS Score

0.0%

EPSS Percentile

0th

SiYuan before v3.8.2 inserts persisted notebook template paths into HTML input value attributes without proper attribute encoding. Attackers can craft malicious template paths that break out of the attribute context and execute JavaScript when a victim opens notebook configuration, enabling same-origin API requests and application state manipulation.

CWE	CWE-79
Vendor	siyuan-note
Product	siyuan
Published	Sep 9, 2026
Last Updated	Sep 9, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

siyuan-note / siyuan

0 < 3.8.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-v6wf-r2gr-rrgf vulncheck.com: https://www.vulncheck.com/advisories/siyuan-before-3.8.2-stored-xss-via-notebook-template-paths