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Vulnerability record · public intelligence
CVE-2026-100634
MEDIUM

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

Published Sep 26, 2026 · Updated Nov 3, 2026

Severity · CVSSMEDIUM · Not scored
Known exploitationNot listed
EPSS / likelihood0.56%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

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

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

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.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
LOW
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. Security advisory ↗
  2. Patch commit ↗
  3. VulnCheck Advisory: SiYuan before v3.8.4 Missing Authorization via siyuan-send-windows ↗

Record history

Published Sep 26, 2026 · Last refreshed Nov 3, 2026