9.8
CRITICAL CVSS 3.1
CVE-2026-86543
knowns before 0.30.0 Unauthenticated Management API Exposure
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.

INFO

Published Date :

Sept. 7, 2026, 11:16 p.m.

Last Modified :

Sept. 7, 2026, 11:16 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-86543 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 CRITICAL [email protected]
CVSS 4.0 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 CRITICAL [email protected]
Solution
Update to version 0.30.0 or later to enforce API authentication and secure network interfaces.
  • Update the software to version 0.30.0 or newer.
  • Ensure the management API is configured with authentication.
  • Restrict network access to essential interfaces only.
  • Review default installation settings for security.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-86543 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-86543 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-86543 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Sep. 07, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V4.0 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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Added CWE CWE-306
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/86xxx/CVE-2026-86543.json">CVE-2026-86543</a>
    Added Reference https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/cli/browser.go#L193-L200
    Added Reference https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/auth.go#L80-L86
    Added Reference https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/routes/tunnel.go#L26-L38
    Added Reference https://github.com/knowns-dev/knowns/commit/878a02cb7cc14f0a592fdfda7a520af3cac500fb
    Added Reference https://github.com/knowns-dev/knowns/releases/tag/v0.30.0
    Added Reference https://github.com/knowns-dev/knowns/security/advisories/GHSA-fc85-99vc-9c75
    Added Reference https://www.vulncheck.com/advisories/knowns-before-0.30.0-unauthenticated-management-api-exposure
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.