EUVD-2026-72561
GHSA-pcf3-jgx6-7m94
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
-
AccessReach Knowns API on 0.0.0.0
-
DeliveryPOST unauthenticated /api/tunnel/start
-
ExploitServer provisions public tunnel
-
ExecutionManagement API republished on public URL
-
ImpactFull remote control of instance
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication required for critical functions
MITRE ATT&CK
1 technique across 1 tactic: Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Requires network reachability to the Knowns management server, which on versions before 0.30.0 binds to all interfaces (0.0.0.0) by default and - on a fresh installation - has no password configured, so no credentials are needed. The critical abuse (/api/tunnel/start) has no authentication check pre-0.30.0. Limiting factors: initial reachability is typically LAN-scoped until a tunnel is provisioned, and instances where the operator has already set a management password are protected against the tunnel-start abuse in patched versions; the exposure is worst on default, freshly installed, network-accessible deployments. |
| Impact | The CVSS 4.0 base of 9.3 (AV:N/AC:L/AT:N/PR:N/UI:N, VC:H/VI:H/VA:H) reflects a genuinely trivial-to-exploit missing-auth condition: no privileges, no user interaction, low complexity. The AV:N/PR:N rating is consistent with the description (all interfaces, no password on fresh install), so unauthenticated network exploitation is well-supported by the data rather than merely inferred. However, real-world risk is bounded by exposure: by default the server binds to a host reachable on the LAN, so initial attackers must be on the same network segment - the /api/tunnel/start abuse is precisely what turns that LAN exposure into internet-wide exposure. No EPSS score, KEV listing, or SSVC decision data was provided; absence of KEV plus an obscure product footprint suggests this is not a mass-exploitation target today. Net: technically critical and easy to exploit where reachable, but the small deployment base and LAN-adjacency of the default install temper the practical urgency compared to a ubiquitous internet-facing service. |
| Exploit ScenarioDerived | An attacker on the same network as a fresh Knowns install (which listens on 0.0.0.0 with no password) sends an unauthenticated POST to /api/tunnel/start. Knowns provisions a public tunnel and republishes its management API at an internet-reachable URL, after which the attacker controls the exposed instance from anywhere. Low attack complexity and no authentication make this a single-request compromise where the server is reachable. |
Get an e-mail when this CVE is exploited, patched or re-scored. Free account.
Alert meAnalysisAIv1 – Sep 07, 2026
Missing authentication in Knowns (knowns-dev/knowns) before 0.30.0 exposes the management API on all network interfaces (0.0.0.0) by default with no password set on fresh installs, letting anyone with network reachability drive the server. Attackers can call the unauthenticated /api/tunnel/start endpoint to spin up a public tunnel that republishes the entire management API at an internet-reachable address, escalating a LAN-only exposure into full public exposure. Reported by VulnCheck and fixed in v0.30.0; publicly available exploit code exists in the sense that the vulnerable endpoints and fix are documented, but no active exploitation is confirmed (not in CISA KEV).
RemediationAI
Vendor-released patch: upgrade to Knowns v0.30.0 or later (fix commit 878a02cb7cc14f0a592fdfda7a520af3cac500fb), which binds the management server to 127.0.0.1 instead of 0.0.0.0, requires --password whenever --tunnel is used, rejects /api/tunnel/start with HTTP 403 until password protection is configured, and blocks password removal (HTTP 409) while a public tunnel is active. If you cannot upgrade immediately, do not start public tunnels, always set a password before running the server, and restrict the management port to loopback or a trusted host - for example front it with a firewall rule limiting the listen port to 127.0.0.1/localhost or block it at the network edge; the trade-off is that LAN clients and the tunnel feature will no longer reach the server until reconfigured. See GHSA-fc85-99vc-9c75 and the VulnCheck advisory for details.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Knowns is a Go-based local tool (CPE cpe:2.3:a:knowns-dev:knowns) that runs an HTTP management/browser server built on the chi router. The root cause is CWE-306 (Missing Authentication for Critical Function): on a fresh install no password is configured, and the server binds to 0.0.0.0 rather than loopback, so critical endpoints - including tunnel provisioning - are reachable without credentials. Source evidence in the v0.30.0 patch (commit 878a02c) confirms this: the fix changes the listener from net.Listen("tcp", "0.0.0.0:%d") to 127.0.0.1, removes the getLocalIP() advertisement of the LAN address, requires --password when --tunnel is used, and adds server-side guards (HTTP 403 on /api/tunnel/start and HTTP 409 on password removal) so a public tunnel cannot exist without password protection. The tunnel feature itself proxies the local API through a public relay (e.g. trycloudflare.com per the test stub), which is why unauthenticated tunnel start is so dangerous.
Know when Knowns gets its next vulnerability
- Watch products and get an email when something new is published
- Check this CVE against your own stack and servers
- Exploit and PoC references, threat intelligence from 22 sources
No credit card · 7-day full trial
Severity by source
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
Fresh installs bind to all interfaces with no password (PR:N, AV:N, AC:L) and unauthenticated API access yields full read/write control of the instance, so C/I/A:H.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
DescriptionCVE.org
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.
Technical POC Analysis
CWE-306 Missing Authentication for Critical Function.
Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.
Executive ViewAI
Knowns management API lacks default authentication and binds to all network interfaces (0.0.0.0), allowing unauthenticated network attackers to access administrative functions and tunnel the entire management interface to the public internet. This converts a potentially isolated management service into a fully exposed attack surface with no access controls, enabling complete compromise of Knowns deployments. Any organization running Knowns prior to version 0.30.0 faces immediate risk of unauthorized administrative access and potential data exfiltration.
Apply vendor patch.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
External control of a filesystem path in Knowns (knowns-dev/knowns) before 0.31.0 lets remote attackers escape the proje
Path traversal in the knowns npm documentation tool (versions ≤ 0.29.1) enables remote unauthenticated attackers to read
Path traversal in knowns before v0.30.0 permits unauthenticated remote attackers to write files outside the designated i
Path traversal in knowns (a Go-based MCP-integrated knowledge management server) before version 0.30.0 allows authentica
Path traversal in the knowns template-preview API (versions before 0.30.0) allows unauthenticated remote attackers to re
Privilege escalation in knowns through 0.33.0 permits authenticated read-only agent sessions to bypass authorization con
Path traversal in the knowns code generation template engine (versions through 0.33.0) allows unauthenticated remote att
Arbitrary binary execution in knowns before 0.30.0 is triggered when a developer opens a repository containing a crafted
Path traversal in the knowns MCP server's handleCodeReplace() function allows unauthenticated network attackers to overw
Authorization bypass in knowns before v0.30.0 allows low-privileged users holding read-restricted sessions to escalate p
Path traversal in knowns through version 0.33.0 allows authenticated AI agent sessions to read arbitrary files anywhere
Server-side request forgery in Knowns ≤0.33.0 enables unauthenticated remote attackers to make the server issue outbound
Exploit-DB