External risk intelligence

SiYuan Cross-Site Scripting and Remote Code Execution Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.9)

CVE-2026-54158

SiYuan is a personal knowledge management system typically deployed as a local desktop application or a private, isolated user workspace. The vulnerability requires a victim to open a specific panel within the application interface, which does not constitute a public-internet-facing or network-reachable service in common deployment patterns.

Cross-site Scripting

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A security vulnerability has been identified in SiYuan, an open-source personal knowledge management system, that could allow for the execution of arbitrary JavaScript. This issue, present before version 3.7.0, arises from how cell content is processed, potentially leading to code injection when specific panels within the application are opened. On desktop versions, this could escalate to remote code execution if an attacker can write malicious content to a synced workspace, affecting all devices that open it.

Malicious JavaScript can run in personal notes.
Affects user data and synced workspaces.
Confirm if SiYuan is used and if data is synced.

Attack Path

How an attacker could exploit the issue

An attacker can inject malicious JavaScript into a SiYuan knowledge management system by manipulating cell content within the attribute-view. This payload, embedded in a text, URL, phone, or mAsset cell, will execute arbitrary JavaScript when a victim opens the block-attribute panel. On Electron desktop versions, this can escalate to remote code execution due to the renderer's node integration. Since attribute values are stored raw and synced across devices, the malicious code persists and can trigger on any device that displays the compromised row.

Attacker needs write access to a synced workspace.
Victim opens the block-attribute panel.
Arbitrary JavaScript execution leading to RCE.

Live Threat

Current exploitation, exposure, and threat context

When a user opens the block-attribute panel in SiYuan, malicious JavaScript could execute within the application's renderer. On Electron desktop environments, this could lead to remote code execution if the attacker has write access to a synced workspace, allowing them to plant a payload that triggers on any device opening a panel with the compromised row.

Arbitrary JavaScript execution in renderer.
Malicious JavaScript in cell content.
Remote code execution on desktop.

Operational Fix

Recommended remediation, mitigation, and detection steps

SiYuan's attribute-view cell renderer is vulnerable to cross-site scripting (XSS) that can lead to remote code execution (RCE) when opening a block-attribute panel. This impacts Electron desktop environments where the renderer runs with `nodeIntegration: true`. Attackers can plant malicious content in synced workspaces, allowing the payload to execute on any device that opens a panel containing the compromised row. Ownership likely resides with application owners and platform teams, with the first practical step being to identify all instances of SiYuan, confirm exposure, and locate accountable owners for remediation planning.

Application owners should address the issue.
Verify all SiYuan instances and workspaces.
Plan remediation based on risk exposure.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is SiYuan?

SiYuan is an open-source personal knowledge management system designed for organizing notes, documents, and data. It functions like a private workspace where users can manage information via features like attribute views or databases, often stored locally or synced across their personal devices.

How does CVE-2026-54158 lead to code execution?

This vulnerability is a form of Cross-Site Scripting (CWE-79). The software fails to properly sanitize input in specific database cell types, allowing attackers to inject malicious code. Because the desktop version uses an Electron framework with broad system permissions enabled, this injected code can escalate into arbitrary command execution on the host machine.

When does this vulnerability trigger?

The payload executes only when a user opens a block-attribute panel containing the compromised data cell. It does not trigger automatically upon simply syncing or viewing the workspace in a standard list; the specific action of interacting with the attribute-view panel is required for the malicious script to run.

Is my SiYuan instance at high risk?

Halo Surface Signal notes that SiYuan is typically deployed as a local or private workspace, making widespread internet exposure unlikely. However, the risk remains if you share workspaces with untrusted users or collaborate in environments where others can modify your synced data, as the payload persists across all devices that open the infected row.

What should I do to secure my SiYuan installation?

The primary response is to update your SiYuan software to version 3.7.0 or later immediately. This version includes the necessary security fixes for the cell renderer that prevent malicious code from breaking out of its container, effectively closing the path for both script injection and system-level access.

References

github.com/siyuan-note/siyuan/security/advisories/GHSA-5xfx-xj4h…

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.