VulnerabilityDeferred
CVE-2026-86543
Attackers can access the unauthenticated /api/tunnel/start endpoint to provision a public tunnel and republish the API at a publicly accessible address.
CRITICAL 9.3EPSS 0.44%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 4.0
- 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.44% probability · 38th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-306
- Source
- disclosure@vulncheck.com
References
- https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/cli/browser.go#L193-L200
- https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/auth.go#L80-L86
- https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/routes/tunnel.go#L26-L38
- https://github.com/knowns-dev/knowns/commit/878a02cb7cc14f0a592fdfda7a520af3cac500fb
- https://github.com/knowns-dev/knowns/releases/tag/v0.30.0
- https://github.com/knowns-dev/knowns/security/advisories/GHSA-fc85-99vc-9c75
- https://www.vulncheck.com/advisories/knowns-before-0.30.0-unauthenticated-management-api-exposure
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.