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TI-2026-51035 Aliases CVE-2026-72809GHSA-3mp7-4rh5-jrv9

SiYuan before v3.7.4 Authentication Bypass via Localhost Trust

Priority MEDIUM 64CWE-290Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · Low · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-290.

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 (127.0.0.1) 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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.003 22nd percentileScored 2026-11-07
Fix Fixed siyuan (siyuan-note): 3.7.4github.com/siyuan-note/siyuan/kernel (Go): 0.0.0-20260723031701-9c16e9851f0b

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
siyuan-notesiyuanbefore 3.7.43.7.4Patch availableCNA
—github.com/siyuan-note/siyuan/kernel (Go)before 0.0.0-20260723031701-9c16e9851f0b0.0.0-20260723031701-9c16e9851f0bPatch availableGHSA-3mp7-4rh5-jrv9
  • siyuan Vendorsiyuan-note Affected before 3.7.4 Fixed in 3.7.4 Patch available CNA
  • github.com/siyuan-note/siyuan/kernel (Go) Vendor— Affected before 0.0.0-20260723031701-9c16e9851f0b Fixed in 0.0.0-20260723031701-9c16e9851f0b Patch available GHSA-3mp7-4rh5-jrv9

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*——siyuan-note
  • cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:* Versions — — ·siyuan-note

Remediation

  • Fix · CNA siyuan (siyuan-note) Fixed in 3.7.4
  • Fix · GHSA-3mp7-4rh5-jrv9 github.com/siyuan-note/siyuan/kernel (Go) Fixed in 0.0.0-20260723031701-9c16e9851f0b Advisory →

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    siyuan-note siyuan 3.7.4

    21 records Highest priority Priority HIGH 12 HIGH, 4 MEDIUM, 5 LOW

    Other records, highest priority first

    • TI-2026-51021 SiYuan before v3.7.4 Information Disclosure via Embed BlockPriority HIGH 79
    • TI-2026-51020 siyuan before v3.7.4 Session Cookie Key Disclosure via getConfPriority HIGH 79
    • TI-2026-51019 SiYuan before v3.7.4 Information Disclosure via /api/system/getConfPriority HIGH 79
    Show all 21 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-72809
  2. 2026-10-03 Alias added: GHSA-3mp7-4rh5-jrv9

References

Advisory 2

Other 2

  • TI-2026-48492 SiYuan before v3.7.3 SQL Injection via searchDocs CVSS 4.0CRITICAL 9.9
  • TI-2026-48491 SiYuan before v3.7.3 SQL Injection via searchEmbedBlock CVSS 4.0CRITICAL 9.9
  • TI-2026-48490 SiYuan before v3.7.3 SQL Injection via fullTextSearchAssetContent CVSS 4.0CRITICAL 9.9
  • TI-2026-47010 SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP CVSS 4.0CRITICAL 10.0
  • TI-2026-26050 SiYuan has directory traversal within its publishing service CVSS 3.1CRITICAL 9.8
  • TI-2026-25256 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API CVSS 3.1CRITICAL 9.8
See all 242 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences