SiYuan before v3.7.4 Authentication Bypass via HTTP Basic Auth (CVE-2026-73046) | HOL Guard CVE

Critical · CVSS 9.8CVE-2026-73046

SiYuan before v3.7.4 Authentication Bypass via HTTP Basic Auth

Answer in brief

CVE-2026-73046 records a Critical severity (CVSS 9.8) vulnerability in SiYuan before v3.7.4 Authentication Bypass via HTTP Basic Auth. The current sources do not mark it as known exploited. The current feed maps siyuan-note/siyuan (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 15, 2026Updated Aug 26, 2026Source checked Sep 30, 2026First seen by HOL Aug 15, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps siyuan-note/siyuan (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
siyuan-note/siyuangeneric	>=0 <3.7.4	3.7.4

Recommended response

Check inventory. Check lockfiles and deployed manifests for siyuan-note/siyuan.
Review the reported fix. Update siyuan-note/siyuan to 3.7.4 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 15, 2026

Sources and claim methodology

Upstream source description

SiYuan before v3.7.4 improperly restricts excessive authentication attempts in the CheckAuth() middleware. The HTTP Basic Authentication branch, which guards nearly the entire /api/* surface, accepts the workspace access code (Conf.AccessAuthCode) as the Basic Auth password but never consults the CAPTCHA/lockout gate or increments the failure counter used by the cookie/session login path. This allows unauthenticated remote attackers to brute-force the admin access code with unlimited automated requests and obtain full RoleAdministrator access to the kernel. A secondary weakness exists because the access code is compared using a non-constant-time string comparison.

Quoted source text, attributed separately from HOL analysis.