Path Traversal in Siyuan-Note Siyuan
CVE-2026-100636
SiYuan versions before v3.8.4 contain a path traversal vulnerability in the exportBrowserHTML endpoint that allows authenticated administrators to write arbitrary HTML content to index.html outside the workspace directory. Attackers can supply a folder parameter with directory traversal sequences to escape the export directory and overwrite index.html in any pre-existing kernel-writable location, enabling stored XSS or workspace defacement.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:L.
EPSS exploit prediction
EPSS: 0.006 (49.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-jf98-m24w-gm9m) (vendor-advisory)
- VulnCheck Advisory: SiYuan before v3.8.4 Path Traversal via exportBrowserHTML folder (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100636?
- CVE-2026-100636 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Path Traversal. CVSS score: 7.6/10. Published 2026-09-26.
- How severe is CVE-2026-100636?
- High severity. CVSS v3 base score is 7.6 out of 10.