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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.004 (28.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-rvcf-q4h8-w6c9 (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-3.8.2-stored-xss-via-bazaar-iconurl (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.