SiYuan before v3.8.2 Stored XSS via incomplete asset blocklist
Priority HIGH 72CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00428 37th percentileScored 2026-11-07
Fix Fixed siyuan (siyuan-note): 3.8.2
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| siyuan-note | siyuan | before 3.8.2 | 3.8.2 | Patch available | CNA |
- siyuan Vendorsiyuan-note Affected before 3.8.2 Fixed in 3.8.2 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:* | — | — | siyuan-note |
- cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:* Versions — — ·siyuan-note
Remediation
- Fix · CNA siyuan (siyuan-note) Fixed in 3.8.2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-84803
- 2026-10-03 Alias added: GHSA-73j8-px8h-3w2h
References
More siyuan-note vulnerabilities
- TI-2026-48492 SiYuan before v3.7.3 SQL Injection via searchDocs CVSS 4.0CRITICAL 9.9
- TI-2026-48491 SiYuan before v3.7.3 SQL Injection via searchEmbedBlock CVSS 4.0CRITICAL 9.9
- TI-2026-48490 SiYuan before v3.7.3 SQL Injection via fullTextSearchAssetContent CVSS 4.0CRITICAL 9.9
- TI-2026-47010 SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP CVSS 4.0CRITICAL 10.0
- TI-2026-26050 SiYuan has directory traversal within its publishing service CVSS 3.1CRITICAL 9.8
- TI-2026-25256 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-84803 · CVE Program
- CVE-2026-84803 · NVD
- FIRST EPSS
- GHSA-73j8-px8h-3w2h · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences