CVE-2026-100634 SiYuan before v3.8.4 Missing Authorization via siyuan-send-windows
An attacker can remotely lock unrelated local workspace windows in SiYuan via IPC, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-100634?
CVE-2026-100634 is a medium-severity missing authorization vulnerability in siyuan-note siyuan, published on 26 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
SiYuan before v3.8.4 does not validate the sender or restrict recipients in the 'siyuan-send-windows' IPC handler of the Electron main process (app/electron/main.js). The handler ignores event.sender and forwards any received payload to every BrowserWindow returned by BrowserWindow.getAllWindows(), including windows belonging to other opened workspaces. A renderer connected to an attacker-controlled remote kernel can therefore send {cmd: "lockscreenByMode"} and have it delivered across the workspace boundary; a sibling workspace window whose lockScreenMode is set to 1 invokes lockScreen(). Repeated messages allow the remote workspace to repeatedly lock unrelated local workspace windows, causing a limited denial of service. No confidentiality, integrity, or code-execution impact was observed.
Weakness: CWE-862
Which versions are affected by CVE-2026-100634?
How do I fix CVE-2026-100634?
No fix has been published for CVE-2026-100634 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-100634 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100634 exists.
Sources
Also known as GHSA-w745-gjg3-r76m, GHSA-wxp7-xpq8-8xpm.