Vulnerability in Siyuan-Note Siyuan
CVE-2026-73046
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (54.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 54.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.008 · change: +0.004
Affected products
- Siyuan-Note Siyuan — versions 0, 3.7.4
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-w3xh-mmmh-r54v (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-http-basic… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-73046?
- CVE-2026-73046 is a critical-severity vulnerability in Siyuan-Note Siyuan, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2026-08-15.
- How severe is CVE-2026-73046?
- Critical severity. CVSS v3 base score is 9.8 out of 10.