CVE-2026-50551: SiYuan: Stored XSS to RCE via Unsanitized Attribute View Asset Cell Content

Synopsis

Stored cross-site scripting (XSS) escalating to remote code execution (RCE) affects SiYuan, the open-source personal knowledge management system, in versions prior to 3.7.0. The vulnerability is reachable over the network by any authenticated low-privilege user, with no victim interaction required, because the Attribute View database asset cell renderer fails to sanitize user-supplied content before rendering it. Successful exploitation gives an attacker full code execution inside the Electron desktop client, along with complete read, write, and availability impact on affected resources. HarborGuard tracks this advisory and will make a patched-image rebuild available the moment an upstream fix is confirmed published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The vulnerable endpoint is exposed over the network, so an attacker must be able to reach the SiYuan service across a network connection.

• AuthenticationRequired

  Any low-privilege authenticated account is sufficient to submit malicious asset cell content; no administrative access is needed.

• Victim interactionNot required

  No victim action is required; the stored XSS payload executes automatically when the Attribute View renders the malicious cell content.

• Attack complexityDetail

  Exploitation is straightforward and condition-free, with no race conditions or special memory layout prerequisites required.

Blast Radius

• Attacker executes arbitrary code inside the Electron desktop client of any user who loads the poisoned Attribute View, achieving full process-level control on that machine.
• Attacker reads all data accessible to the desktop client, including stored notes, attachments, API tokens, and session credentials.
• Attacker modifies or deletes any persisted content in the knowledge base, including notes, database entries, and linked assets.
• Attacker disrupts availability of the desktop client and any locally accessible services, crashing or locking out the affected user.