---
id: CVE-2026-72809
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…
summary: >-
  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…
severity: high
cvss: 8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H'
cwe:
  - CWE-290
published: '2026-08-12'
updated: '2026-08-14'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72809'
references:
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72809'
  - url: >-
      https://github.com/siyuan-note/siyuan/commit/9c16e9851f0b5d7ed179e5c2fca15a7724666871
  - url: 'https://github.com/siyuan-note/siyuan'
tags:
  - nvd
  - osv
  - go
epss: 0.00206
epssPercentile: 0.11046
ingestedAt: '2026-08-15T21:29:27.245Z'
aliases:
  - GHSA-3mp7-4rh5-jrv9
  - GO-2026-6386
ecosystem: go
vendor: siyuan-note
product: github.com/siyuan-note/siyuan/kernel
affected:
  - github.com/siyuan-note/siyuan/kernel < 0.0.0-20260723031701-9c16e9851f0b
patched:
  - github.com/siyuan-note/siyuan/kernel 0.0.0-20260723031701-9c16e9851f0b
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-72809)

Affected packages:

- `github.com/siyuan-note/siyuan/kernel < 0.0.0-20260723031701-9c16e9851f0b`

Patched in:

- `github.com/siyuan-note/siyuan/kernel 0.0.0-20260723031701-9c16e9851f0b`

Source: https://osv.dev/vulnerability/GHSA-3mp7-4rh5-jrv9