SiYuan up to 3.6.3 Bazaar cross site scripting

Summaryinfo

A vulnerability marked as problematic has been reported in SiYuan up to 3.6.3. The impacted element is an unknown function of the component Bazaar Handler. This manipulation causes cross site scripting. This vulnerability is handled as CVE-2026-40922. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in SiYuan up to 3.6.3. It has been declared as problematic. Affected by this vulnerability is an unknown code of the component Bazaar 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. The summary by CVE is:

SiYuan is an open-source personal knowledge management system. In versions 3.6.1 through 3.6.3, a prior fix for XSS in bazaar README rendering (incomplete fix for CVE-2026-33066) enabled the Lute HTML sanitizer, but the sanitizer does not block iframe tags, and its URL-prefix blocklist does not effectively filter srcdoc attributes which contain raw HTML rather than URLs. A malicious bazaar package author can include an iframe with a srcdoc attribute containing embedded scripts in their README. When other users view the package in SiYuan's marketplace UI, the payload executes in the Electron context with full application privileges, enabling arbitrary code execution on the user's machine. This issue has been fixed in version 3.6.4.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-40922 since 04/15/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 3.6.4 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch b382f50e1880ed996364509de5a10a72d7409428 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Name

• SiYuan

Version

• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3

License

• open-source

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