CVE-2026-100634

SiYuan before v3.8.4 Missing Authorization via siyuan-send-windows

Published Sep 26, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Siyuan
Siyuan siyuan
Vendors & Products Siyuan
Siyuan siyuan
Type Values Removed Values Added
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.
Title SiYuan before v3.8.4 Missing Authorization via siyuan-send-windows
First Time appeared B3log
B3log siyuan
Weaknesses CWE-862
CPEs cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
Vendors & Products B3log
B3log siyuan
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 8, 2026, 3:51 PM
Reserved
Sep 26, 2026, 2:31 AM
Status
Deferred
Published
Sep 26, 2026, 2:16 PM
Modified
Oct 8, 2026, 4:16 PM