Authentication Bypass in SiYuan by SiYuan Note

CVE-2026-73046

What is CVE-2026-73046?

SiYuan versions prior to 3.7.4 have a significant vulnerability in their CheckAuth() middleware, which improperly restricts the number of authentication attempts. This flaw allows remote attackers to continuously send automated requests to exploit the HTTP Basic Authentication mechanism. Instead of enforcing CAPTCHA or a lockout mechanism, the workspace access code is accepted without limitations, leading to potential unauthorized access. Additionally, the method used for comparing access codes is not secure, making it susceptible to timing attacks. As a result, attackers can gain full administrator privileges without proper authentication.

References