SiYuan versions prior to 3.7.2 contain a cross‑site scripting flaw in the siyuan:// protocol handler. When a link of the form siyuan://plugins/<name> points to a non‑installed plugin, the application opens a custom tab and inserts the link’s icon parameter into the tab header using innerHTML without escaping it. This allows an attacker to inject an <img onerror=…> element. Because the SiYuan Desktop renderer runs with nodeIntegration:true, the injected JavaScript can call Node's require('child_process').execSync, giving the attacker the ability to execute arbitrary operating‑system commands, effectively compromising the host machine.

The affected vendor is SiYuan Note, product SiYuan. All releases before 3.7.2 are vulnerable; the issue manifests when a siyuan://plugins/<name> link references a plugin that is not installed.

The CVSS score of 9.4 indicates critical severity, though the EPSS score is reported as less than 1 % showing a low but nonzero exploitation probability. The vulnerability is not listed in the CISA KEV catalog. The likely attack vector is through a crafted siyuan:// link presented to a user; success requires user interaction to open the link. Once executed, the attacker can run arbitrary OS commands with the privileges of the SiYuan process.