TI-2026-51265 Aliases CVE-2026-73056 GHSA-v5mj-g3f2-mwr9

SiYuan kernel before 3.7.4 Unthrottled Brute-Force via API Token

HIGH 81CWE-307Published 2026-08-16 · Updated 2026-08-17

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-307.

Summary

SiYuan kernel versions before 3.7.4 contain an improper restriction of excessive authentication attempts vulnerability in the CheckAuth() middleware. The middleware accepts the API token (Conf.Api.Token) via an Authorization header (Token/Bearer) or a ?token= query parameter, and neither path is protected by the application's CAPTCHA/lockout mechanism (NeedCaptcha/WrongAuthCount). As a result, an unauthenticated remote attacker can perform unlimited automated guesses of the API token, particularly when a short or weak custom token has been configured, and upon success gains full RoleAdministrator access enabling arbitrary file operations and SQL queries.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.0079 56th percentileScored 2026-11-07

Fix Fixed siyuan (siyuan-note): 3.7.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Total

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

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
siyuan-note	siyuan	before 3.7.4	3.7.4	Patch available	CNA

siyuan Vendorsiyuan-note Affected before 3.7.4 Fixed in 3.7.4 Patch available CNA

CPE names Threatist (inferred) · 1

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

CPE	Versions	Role	Vendor
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

Timeline

2026-10-02 Threatist record created from CVE-2026-73056
2026-10-03 Alias added: GHSA-v5mj-g3f2-mwr9

References

Advisory 1

GitHub Security Advisory (GHSA-m6w6-p7pc-fpg2)

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