Vulnerability in Siyuan-Note Siyuan
CVE-2026-100637
SiYuan versions before v3.8.4 contain a path traversal vulnerability in the checkoutRepo endpoint that allows authenticated administrators to write JSON files outside the workspace. Attackers can supply a sessionID parameter containing directory traversal sequences to overwrite arbitrary JSON files in pre-existing kernel-writable directories outside workspace boundaries.
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-jhmh-hr4g-c5g2) (vendor-advisory)
- VulnCheck Advisory: SiYuan before v3.8.4 Path Traversal via checkoutRepo sessionID (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100637?
- CVE-2026-100637 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-2026-100637?
- High severity. CVSS v3 base score is 7.6 out of 10.