An unauthenticated authorization bypass in SiYuan before version 3.7.4 allows attackers to access sensitive data endpoints without valid credentials.

This vulnerability, classified as CWE-862, stems from a missing authorization check on a specific development endpoint. Because the endpoint requires no authentication, an unauthenticated attacker can query sensitive data by interacting directly with the application.

The ability for unauthenticated users to access sensitive endpoints can lead to significant information disclosure. With a CVSS score of 8.6, this vulnerability allows unauthorized actors to harvest data, potentially leading to a breach of internal notes or organizational knowledge bases, which may contain proprietary or sensitive information.

Immediate Action: Update the SiYuan application to version 3.7.4 or later to ensure proper authorization enforcement on all endpoints.

Proactive Monitoring: Review application access logs for suspicious requests to API endpoints, particularly those targeting attribute views or search targets from unauthorized IP addresses.

Compensating Controls: Deploy a Web Application Firewall (WAF) to block unauthorized access to administrative or internal-facing API endpoints if an immediate update is not feasible.

Public Exploit Available: Unknown

Given the ease of access provided by this vulnerability, it must be addressed urgently. Organizations should apply the update to version 3.7.4 immediately to prevent unauthorized data exposure through these exposed endpoints.