CVE-2026-58197 ToolHive: containerized MCP servers can reach host services via host.docker.internal, enabling lateral movement
Attackers can exploit missing network isolation and authentication in ToolHive to access host services and manipulate MCP servers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-58197?
CVE-2026-58197 is a high-severity missing authorization vulnerability in stacklok toolhive, published on 18 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
ToolHive is a utility designed to simplify the deployment and management of Model Context Protocol servers. Prior to ToolHive CLI 0.30.1 and ToolHive Studio 0.38.0, locally run MCP server containers use the default network permission profile without network isolation, permitting access to host.docker.internal while ToolHive API and MCP proxy endpoints are reachable without authentication. A malicious or compromised MCP server can use the Docker gateway to contact host-local services, other ToolHive-managed MCP proxies, or the ToolHive control plane without escaping the container. This access can expose data and logs, invoke sibling MCP tools, alter process or workload state, and disrupt services. ToolHive Studio additionally sends network_isolation as false and overrides the backend's secure isolation default. This issue is fixed in ToolHive CLI 0.30.1 and ToolHive Studio 0.38.0.
Which versions are affected by CVE-2026-58197?
3 open source packages ship an affected version, including github.com/stacklok/toolhive.
| Package | Affected | Fixed in |
|---|---|---|
github.com/stacklok/toolhive Go | All versions | 0.30.1 |
github.com/stacklok/toolhive Go | All versions | 0.30.1 |
github.com/stacklok/toolhive Go | All versions | 0.30.1 |
How do I fix CVE-2026-58197?
Upgrade github.com/stacklok/toolhive to 0.30.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-58197 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58197 exists.
Sources
Also known as GHSA-qg2g-g9w3-m5h8, GO-2026-6526.