{"cve":"CVE-2026-72809","nvd":{"published":"2026-08-12T20:17:53.110","modified":"2026-10-23T22:10:00.160","status":"Deferred","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.","cvss_v4":{"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","score":7.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H","score":8.0},"cwes":["CWE-290"],"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","https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9"],"products":[],"source":"nvd","synced_at":"2026-10-24T16:53:35.584907681+00:00"},"epss":{"cve":"CVE-2026-72809","score":0.003,"percentile":0.22468,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-3mp7-4rh5-jrv9","url":"https://osv.dev/vulnerability/GHSA-3mp7-4rh5-jrv9","summary":"SiYuan: Localhost-trust admin bypass on auth-code-gated endpoints, with potential remote reachability via the fixed-port proxy","modified":"2026-09-10T15:25:53.562584185Z","packages":[{"ecosystem":"Go","name":"github.com/siyuan-note/siyuan/kernel","purl":"pkg:golang/github.com/siyuan-note/siyuan/kernel","ranges":["<0.0.0-20260723031701-9c16e9851f0b"],"fixed":["0.0.0-20260723031701-9c16e9851f0b"]}]},{"id":"GO-2026-6386","url":"https://osv.dev/vulnerability/GO-2026-6386","summary":"SiYuan: Localhost-trust admin bypass on auth-code-gated endpoints, with potential remote reachability via the fixed-port proxy in github.com/siyuan-note/siyuan/kernel","modified":"2026-09-10T15:15:12.906830252Z","packages":[{"ecosystem":"Go","name":"github.com/siyuan-note/siyuan/kernel","purl":"pkg:golang/github.com/siyuan-note/siyuan/kernel","ranges":["<0.0.0-20260723031701-9c16e9851f0b"],"fixed":["0.0.0-20260723031701-9c16e9851f0b"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}