CVE-2026-84803SiYuan before v3.8.2 Stored XSS via incomplete asset blocklist
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 9.0 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Sep 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
siyuan-note siyuan siyuan_note:siyuan (from the name) | before 3.8.2; 3.8.2 not affected | CNA record |
References
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7h8j-qw37-w46gvendor-advisory
- https://www.vulncheck.com/advisories/siyuan-before-3.8.2-stored-xss-via-incomplete-asset-blocklistthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.