SiYuan is a personal knowledge management system that uses an Electron desktop client. Before version 3.6.4 a table caption entered in a note is stored without proper escaping. When the note is rendered, the caption data is unescaped into HTML, creating a stored cross‑site scripting sink. Because the Electron renderer runs with Node.js integration enabled and context isolation disabled, the malicious JavaScript runs with full Node.js privileges, allowing an attacker to execute arbitrary code on the victim’s machine. This single flaw provides complete compromise of the desktop application.

All users running SiYuan Electron desktop client editions prior to 3.6.4 are affected. The vulnerability is present in the Siyuan application bundled with the Electron framework as sold by the vendor Siyuan‑Note. It is fixed starting with version 3.6.4, which is the only version that has the proper escaping implemented.

The CVSS score of 9.1 indicates a critical severity. The CVE is not listed in the CISA KEV catalog and no EPSS score is available, so the current public exploitation probability is unknown. The expected attack vector is remote: an attacker must first create a malicious note with a crafted table caption and then cause a victim to sync and open that note, for example by sharing a workspace. The vulnerability requires the victim to have the updated Electron client running with node integration; if a user is running a patched or newer version or has disabled node integration, exploitation is blocked.