CVE-2026-55887
MCP Gateway allows easy and secure running and deployment of MCP servers. From 0.21.0 until 0.42.2, Docker MCP Gateway YAML-unmarshalled the attacker-controlled io.docker.server.metadata OCI image label into the broad catalog.Server structure for direct docker:// references and catalog snapshot imports in pkg/oci/self_contained.go and pkg/workingset/workingset.go. Runtime-shaping fields including Volumes, User, and ExtraHosts were then appended to the docker run argument vector without an origin allowlist, allowing a malicious image author to request host filesystem or Docker socket mounts and UID 0 execution when a victim selected or pulled the image. This container-creation-time boundary bypass can execute arbitrary code on the host and is not prevented by no-new-privileges because no in-container privilege escalation is required. This issue is fixed in version 0.42.2.
- CVSS 4.0
- 8.7
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 12% of CVEs (scores of 2026-10-25)
- CWE
- CWE-88
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-r2xf-7jw5-pjg6 | Go | github.com/docker/mcp-gateway | >=0.21.0 <0.42.2 | 0.42.2 |
| GO-2026-5604 | Go | github.com/docker/mcp-gateway | >=0.21.0 <0.42.2 | 0.42.2 |
References
- https://github.com/docker/mcp-gateway/commit/306d2d94a3b526f43281313321bf784f2d46a7fe
- https://github.com/docker/mcp-gateway/commit/439b2200d9e26a4ff414aeb043785df45a78422b
- https://github.com/docker/mcp-gateway/pull/498
- https://github.com/docker/mcp-gateway/releases/tag/v0.42.2
- https://github.com/docker/mcp-gateway/security/advisories/GHSA-r2xf-7jw5-pjg6