CVE-2026-100646 SiYuan before v3.8.4 Authentication Bypass via Missing Origin Header

SiYuan is a self-hosted personal knowledge management system. In versions up to and including 3.8.3, the kernel's authentication guards CheckAuth in kernel/model/session.go and IsSessionOriginAllowed in kernel/util/net.go fail open when the HTTP Origin header is absent, on the incorrect assumptio...