Mermaid

SiYuan is vulnerable to zero-click NTLM hash theft on Windows and blind SSRF on all platforms due to insecure Mermaid.js configuration, where a malicious Mermaid diagram containing a protocol-relative URL can be injected into a note, causing the Electron client to fetch the URL, triggering SMB authentication on Windows and sending the victim's NTLMv2 hash to the attacker. On macOS and Linux, the request acts as a tracking pixel and blind SSRF.