{"apiVersion":"1.0","identifier":"CVE-2026-72809","description":"SiYuan versions <= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel-s CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including /api/system/exit, getNetwork, getWorkspaceInfo, /assets/*, and /export/*). These localhost bypasses sit outside the access auth code gate, so they apply even when an access auth code is configured. Because the fixed-port reverse proxy forwards requests to the kernel over loopback without injecting an authentication token and does not configure trusted proxies, a request forwarded through this proxy reaches the kernel with RemoteAddr = 127.0.0.1. If the fixed-port proxy is bound to a network interface, this could allow a remote unauthenticated attacker to obtain admin access on the affected endpoints; however, per the advisory this remote forwarding behavior was established only by code inspection and was not reproduced end-to-end.","publishedAt":"2026-08-12T20:17:53","lastModifiedAt":"2026-08-26T16:56:50","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-72809","cvssScore":8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H","epssProbability":0.00206,"riskScore":0.81,"affectedProduct":"SiYuan","affectedVersions":"<=3.7.2","vulnerabilityType":"Web app","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-72809","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-72809","en":"https://www.redsauce.net/en/cves/CVE-2026-72809","fr":"https://www.redsauce.net/fr/cves/CVE-2026-72809","pt":"https://www.redsauce.net/pt/cves/CVE-2026-72809","de":"https://www.redsauce.net/de/cves/CVE-2026-72809","sk":"https://www.redsauce.net/sk/cves/CVE-2026-72809","el":"https://www.redsauce.net/el/cves/CVE-2026-72809"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-72809"}}