SiYuan up to 3.6.1 Block cross site scripting

Summaryinfo

A vulnerability labeled as problematic has been found in SiYuan up to 3.6.1. Affected by this vulnerability is an unknown functionality of the component Block Handler. Executing a manipulation can lead to cross site scripting. The identification of this vulnerability is CVE-2026-34585. The attack can only be executed locally. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic was found in SiYuan up to 3.6.1. This vulnerability affects an unknown part of the component Block Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

SiYuan is a personal knowledge management system. Prior to version 3.6.2, a vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import -> SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. This issue has been patched in version 3.6.2.

The advisory is available at github.com. This vulnerability was named CVE-2026-34585 since 03/30/2026. The exploitation appears to be easy. Local access is required to approach this attack. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

Upgrading to version 3.6.2 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Name

• SiYuan

Version

• 3.6.0
• 3.6.1

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