Auth bypass in Knowns-Dev Knowns
CVE-2026-86543
knowns versions before 0.30.0 serve the management API without authentication on all network interfaces by default, with no password required on fresh installations. Attackers can access the unauthenticated /api/tunnel/start endpoint to provision a public tunnel and republish the API at a publicly accessible address.
Vulnerability class: Broken Authentication
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.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (release-notes)
- disclosure@vulncheck.com (vendor-advisory)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-86543?
- CVE-2026-86543 is a critical-severity vulnerability in Knowns-Dev Knowns, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-09-07.
- How severe is CVE-2026-86543?
- Critical severity. CVSS v3 base score is 9.8 out of 10.