VULNERABILITY INTELLIGENCE
CVE-2026-84803
CVSS score9 CRITICAL
EPSS probability0.43%
CISA KEVNot currently listed
Published2026-09-02
Last modified2026-09-02
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Description
SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in asset serving due to an incomplete extension blocklist that misses script-capable file types. Attackers can upload files with extensions like .xht, .ehtml, .xsl, .xbl, or .rdf that resolve to executable media types and execute JavaScript to steal API tokens and compromise workspaces.
Weakness classification
- disclosure@vulncheck.com: CWE-79