CVE-2026-100637 SiYuan before v3.8.4 Path Traversal via checkoutRepo sessionID
Authenticated administrators can exploit a path traversal flaw in the checkoutRepo endpoint to overwrite arbitrary JSON files outside the workspace.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-100637?
CVE-2026-100637 is a high-severity path traversal vulnerability in siyuan-note siyuan, published on 26 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Weakness: CWE-73
Which versions are affected by CVE-2026-100637?
How do I fix CVE-2026-100637?
No fix has been published for CVE-2026-100637 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-100637 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100637 exists.
Sources
Also known as GHSA-4fq5-2r2r-5cw9, GHSA-jhmh-hr4g-c5g2.