What is CVE-2026-87812?

CVE-2026-87812 is a medium-severity vulnerability in Siyuan-Note Siyuan, classified under Cross-site Scripting. CVSS score: 6.8/10. Published 2026-09-09.

How severe is CVE-2026-87812?

Medium severity. CVSS v3 base score is 6.8 out of 10.

XSS in Siyuan-Note Siyuan

CVE-2026-87812

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in Bazaar package cards where the iconURL metadata is inserted directly into HTML img src attributes without escaping. Attackers can inject malicious URLs with event handlers that execute JavaScript in the authenticated SiYuan origin when users view Bazaar listings, enabling API requests and application state manipulation.

Vulnerability class: XSS (Cross-Site Scripting)

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.

Affected products

Siyuan-note Siyuan

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-87812?: CVE-2026-87812 is a medium-severity vulnerability in Siyuan-Note Siyuan, classified under Cross-site Scripting. CVSS score: 6.8/10. Published 2026-09-09.
How severe is CVE-2026-87812?: Medium severity. CVSS v3 base score is 6.8 out of 10.