A critical missing authorization vulnerability in SiYuan allows unauthenticated remote attackers to gain full administrative control over the affected installation.

This vulnerability is a missing authorization flaw in the kernel API, where the POST /mcp endpoint lacks proper role enforcement. This allows an unauthenticated remote attacker to perform unauthorized file operations, extract sensitive configuration tokens, and execute arbitrary code on the host system.

The potential impact of this vulnerability is total system compromise, including the ability to read, modify, or delete sensitive data and execute malicious payloads. Given the CVSS score of 10.0, this represents a critical risk to confidentiality, integrity, and availability, potentially leading to a complete breach of the host environment.

Immediate Action: Update siyuan-note siyuan to version 3.7.2 or later immediately to apply the necessary authorization checks.

Proactive Monitoring: Review system access logs for anomalous requests to the /mcp endpoint and monitor file system activity for unexpected modifications in the data/plugins/ directory.

Compensating Controls: If immediate patching is not feasible, restrict network access to the SiYuan interface and disable the Publish server functionality to prevent anonymous access to the vulnerable API.

Public Exploit Available: No (no confirmed public exploit exists in available data).

This is a critical security flaw that requires immediate attention. Organizations must prioritize upgrading to version 3.7.2 to eliminate the risk of unauthenticated remote administrative takeover.