# CVE-2026-58197: ToolHive containerized MCP servers host service access via host.docker.internal

Source: https://junglewise.ai/threats/cve-2026-58197-toolhive-containerized-mcp-servers-host-service-access-via-host  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-58197 · Severity: high · CVSS 8.8 · Published 2026-09-18

ToolHive is a container orchestration system for AI-powered MCP (Model Context Protocol) servers. By default, ToolHive containers can reach services on the host machine—including the ToolHive control plane itself, other MCP servers, and any other localhost services—via Docker's host.docker.internal mechanism. Combined with unauthenticated API endpoints, this allows a compromised or malicious MCP server to attack other services on the host without escaping the container, bypassing ToolHive's core security model.

Technologies: [github.com/stacklok/toolhive (Go)](https://junglewise.ai/threats/technologies/github-com-stacklok-toolhive). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-58197 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-58197 being exploited in the wild.

**How severe is CVE-2026-58197?** High severity, with a CVSS score of 8.8, published 18 September 2026.

**Which products and versions are affected?** github.com/stacklok/toolhive (Go) < 0.30.1, SEMVER:introduced=0,fixed=0.30.1.

**Is there a fix for CVE-2026-58197?** Yes. github.com/stacklok/toolhive (Go): upgrade to 0.30.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-58197 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-58197?** Check whether you run github.com/stacklok/toolhive (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/stacklok/toolhive (Go): upgrade to 0.30.1 or later

  ```sh
  go get github.com/stacklok/toolhive@v0.30.1
  ```


## Technical details

The vulnerability is a combination of three design weaknesses: (1) the default `insecure_allow_all: true` permission profile permits unrestricted outbound connections, (2) ToolHive's MCP proxy endpoints (port 50444 and others) lack authentication, and (3) Docker's host.docker.internal DNS resolves to the host machine, allowing containers to reach localhost services. An attacker with code execution inside a container can perform MCP handshakes with the host's ToolHive API and other MCP server proxies, enumerate and call their tools (e.g., execute_command, write_file), pivot to privileged native MCP servers, or reach other host services like Kubernetes APIs or LLM endpoints. No container escape or additional vulnerability is required; network access alone is sufficient for lateral movement and privilege escalation.

## Affected products

- ToolHive ToolHive v0.9.3 and default configuration

## Identifiers

- CVE-2026-58197
- GHSA-qg2g-g9w3-m5h8
- GO-2026-6526

## Timeline

- 2026-09-18: disclosed: Advisory published on GitHub
- 2026: other: CVE-2026-58197 assigned

## Related threats

- [Stacklok ToolHive SSRF in remote MCP server authentication discovery](https://junglewise.ai/threats/cve-2026-58196-stacklok-toolhive-ssrf-in-remote-mcp-server-authentication)
- [Stacklok ToolHive SSRF bypass via IPv6 NAT64 ranges](https://junglewise.ai/threats/cve-2026-54450-stacklok-toolhive-ssrf-bypass-via-ipv6-nat64-ranges)