# CVE-2026-73046 — siyuan-note siyuan

> As of 2026-08-15, CVE-2026-73046 is a CRITICAL-severity vulnerability in siyuan-note siyuan, CVSS v3.1 9.8, EPSS 0.4% (35.5th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-73046 as of 2026-08-15; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-15

## What is 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.

The record classifies CVE-2026-73046 under weakness class [CWE-307](https://intel.threadlinqs.com/cwe/CWE-307). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 51 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.8 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **CVSS v4.0 base score:** 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.4% probability of exploitation in the next 30 days, higher than 35.5% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 6.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-15

## Is CVE-2026-73046 being exploited?

It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [siyuan-note](https://intel.threadlinqs.com/vendors/siyuan-note): siyuan

## How to fix CVE-2026-73046

No vendor patch reference has been recorded for CVE-2026-73046 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-73046

No threat campaign in the Threadlinqs corpus currently references CVE-2026-73046, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-08-16.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/siyuan-note/siyuan/security/advisories/GHSA-w3xh-mmmh-r54v)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-http-basic-auth)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-73046
Full detection coverage and IOCs for threats exploiting CVE-2026-73046 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp