Authentication Bypass in SiYuan Publishing Service by SiYuan

CVE-2026-100635

What is CVE-2026-100635?

SiYuan versions before 3.8.4 are susceptible to an authentication bypass vulnerability within the publish service. This flaw arises because session cookies are issued over unencrypted HTTP connections, lacking Secure and SameSite attributes. An attacker positioned on the network can intercept a valid publish-visitor-session-id cookie during a Basic Authentication exchange. With this capability, the attacker may replay the cookie to gain unauthorized access to publish endpoints without requiring the actual account password, potentially compromising user data and the integrity of the service.

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