Vulnerability in Siyuan-Note Siyuan
CVE-2026-100638
SiYuan versions before v3.8.4 contain a path traversal vulnerability in the setNotebookIcon endpoint that allows authenticated administrators to create arbitrary directory trees and write files outside the workspace boundary. Attackers can supply directory traversal sequences in the notebook parameter to escape the workspace data directory and write conf.json files to arbitrary locations accessible by the kernel process.
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 (46.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 46.5% 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-6h8x-6mph-7438) (vendor-advisory)
- VulnCheck Advisory: SiYuan before v3.8.4 Path Traversal via setNotebookIcon (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100638?
- CVE-2026-100638 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under External Control of File Name or Path. CVSS score: 7.6/10. Published 2026-09-26.
- How severe is CVE-2026-100638?
- High severity. CVSS v3 base score is 7.6 out of 10.