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Critical 9.8Published Aug 15, 2026

CVE-2026-73046SiYuan before v3.7.4 Authentication Bypass via HTTP Basic Auth

Updated under an hour ago ()

Does this affect you?

It affects siyuan-note siyuan. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-307
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
VulnCheck
NVD analysis
Deferred
Record last updated
Aug 17, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
siyuan-note siyuan
siyuan_note:siyuan (from the name)
before 3.7.4; 3.7.4 not affected
CNA record

References

  • vendor-advisory
  • third-party-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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