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High, CVSS 8.8amended

ToolHive: containerized MCP servers can reach host services via host.docker.internal, enabling lateral movement

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

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (github.com/stacklok/toolhive 0.30.1), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
8.8 · CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS
  • CVE-2026-58197: 0.37% estimated exploitation activity in the next 30 days; percentile 31.22 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary A containerized MCP server running with the default network permission profile (insecureallowall: true) can reach host-local services via host.docker.internal. This includes the ToolHive API itself, other ToolHive-managed MCP server proxies, and any other service listening on the host's localhost. Combined with the unauthenticated ToolHive API and MCP proxy endpoints, this enables a compromised or malicious MCP server to perform lateral movement without any container escape. Severity High — This bypasses the container isolation model that is ToolHive's core security value proposition. Reproduction All tests performed from inside the filesystem MCP container (docker.io/mcp/filesystem:latest), started with default settings via thv run filesystem -- /tmp. 1. Container can reach the ToolHive control plane MCP endpoint Result: Full MCP handshake succeeds: 2. Container can connect to another MCP server's proxy and call its tools Result: Returns the full tool list of the target MCP…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-qg2g-g9w3-m5h8

  2. Revision 2 · amended ·

    Amended from osv record GO-2026-6526

  3. Revision 1 · created ·

    Published from osv record GHSA-qg2g-g9w3-m5h8

Agent brief

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# Patch Next advisory brief: CVE-2026-58197

Advisory: ToolHive: containerized MCP servers can reach host services via host.docker.internal, enabling lateral movement
IDs: CVE-2026-58197, GHSA-qg2g-g9w3-m5h8
Record: https://patchnext.com/advisories/cve-2026-58197 (revision 3, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/stacklok/toolhive 0.30.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/stacklok/toolhive: affected < 0.30.1; fixed in 0.30.1

## Suggested inspection (read-only)
- Go github.com/stacklok/toolhive: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/stacklok/toolhive.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-qg2g-g9w3-m5h8 (OSV record GHSA-qg2g-g9w3-m5h8 lists affected ranges: Go github.com/stacklok/toolhive >=0 <0.30.1 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6526 (OSV record GO-2026-6526 lists affected ranges: Go github.com/stacklok/toolhive >=0 <0.30.1 (fixed))
- Verified: https://github.com/advisories/GHSA-qg2g-g9w3-m5h8 (GitHub-reviewed advisory GHSA-qg2g-g9w3-m5h8 lists affected ranges: Go github.com/stacklok/toolhive >=0 <0.30.1)

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