CVE-2026-73056 SiYuan kernel before 3.7.4 Unthrottled Brute-Force via API Token
Unauthenticated attackers can brute-force API tokens due to missing rate limiting, gaining administrator access to execute arbitrary code and modify data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-73056?
CVE-2026-73056 is a critical authentication bypass vulnerability in siyuan-note siyuan, published on 16 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-307
Which versions are affected by CVE-2026-73056?
How do I fix CVE-2026-73056?
No fix has been published for CVE-2026-73056 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-73056 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73056 exists.
Sources
Also known as GHSA-v5mj-g3f2-mwr9.