{"id":"CVE-2026-72809","revision":"e2f923d107bd4c1182d6a8b15b06a647","records":[{"revision":"e2f923d107bd4c1182d6a8b15b06a647","observedAt":"2026-10-25T15:19:03.401+00:00","statement":{"source":"nvd","id":"CVE-2026-72809","aliases":[],"title":"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)…","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.","state":0,"publishedAt":"2026-08-12T20:17:53.11+00:00","modifiedAt":"2026-10-23T22:10:00.16+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · disclosure@vulncheck.com · Secondary","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":7.1,"severity":"HIGH"},{"system":"CVSS 3.1 · disclosure@vulncheck.com · Secondary","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H","score":8,"severity":"HIGH"}],"references":["https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9","https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-72809","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-290"],"productCriteria":[],"sourceDates":{"published":"2026-08-12T20:17:53.110","lastModified":"2026-10-23T22:10:00.160"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-72809","identifiers":["CVE-2026-72809"]},"retained":false,"historicalAffected":[]}],"coverage":[]}