SiYuan up to 3.6.x HTML Attribute JSON.stringify HTML injection

Summaryinfo

A vulnerability, which was classified as problematic, has been found in SiYuan up to 3.6.x. Affected is the function JSON.stringify of the component HTML Attribute Handler. Performing a manipulation results in HTML injection. This vulnerability is reported as CVE-2026-55570. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in SiYuan up to 3.6.x. This affects the function JSON.stringify of the component HTML Attribute Handler. The manipulation with an unknown input leads to a html injection vulnerability. CWE is classifying the issue as 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. This is going to have an impact on integrity. The summary by CVE is:

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, it does not escape the untrusted fields (name, version, author, description) when they are serialized into the data-obj HTML attribute of each marketplace card. Because the attribute is single-quoted and the value is produced with JSON.stringify() (which does not escape ', ), a package whose name contains a single quote breaks out of the attribute and injects arbitrary HTML. In the desktop client the main BrowserWindow runs with nodeIntegration: true, contextIsolation: false, so the injected markup escalates from DOM XSS to arbitrary OS command execution. This is the same root cause and same impact as the original advisory, reached through a sibling sink the patch did not cover. This vulnerability is fixed in 3.7.0.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-55570 since 06/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 3.7.0 eliminates this vulnerability.

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Productinfo

Name

• SiYuan

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6

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