AUGUST 15, 2026
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Case File

CVE-2026-72809

HIGH · CVSS 8 EPSS 0.21% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-12 · Last synced 2026-08-15

CyberRota Analysis

AI-Generated

Versions of SiYuan up to v3.7.2 are vulnerable to an authentication bypass in the CheckAuth function, allowing any request from the loopback address (127.0.0.1) to gain administrator privileges on specific endpoints, regardless of configured access controls. This vulnerability poses a high risk as it could enable remote unauthenticated attackers to exploit misconfigured proxies that forward requests to the kernel. Organizations using affected versions should prioritize patching to v3.7.4 or later to mitigate potential unauthorized access.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-72809
Severity
HIGH
CVSS
8
EPSS
0.21%

Original NVD 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.