{"id":"CVE-2026-55887","state":"PUBLISHED","title":"MCP Gateway: Argument injection via OCI image label YAML in Docker MCP Gateway","description":"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.","publishedAt":"2026-09-15T15:45:36.420Z","updatedAt":"2026-09-15T18:02:09.186Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["docker mcp-gateway"],"affected":[{"vendor":"docker","product":"mcp-gateway","versions":[{"version":">= 0.21.0, < 0.42.2","status":"affected"}]}],"references":["https://github.com/docker/mcp-gateway/security/advisories/GHSA-r2xf-7jw5-pjg6","https://github.com/docker/mcp-gateway/pull/498","https://github.com/docker/mcp-gateway/commit/306d2d94a3b526f43281313321bf784f2d46a7fe","https://github.com/docker/mcp-gateway/commit/439b2200d9e26a4ff414aeb043785df45a78422b","https://github.com/docker/mcp-gateway/releases/tag/v0.42.2"],"weaknesses":["CWE-88"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55887.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55887","state":"PUBLISHED","datePublished":"2026-09-15T15:45:36.420Z","dateUpdated":"2026-09-15T18:02:09.186Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-17T16:59:42.760Z"},"containers":{"cna":{"title":"MCP Gateway: Argument injection via OCI image label YAML in Docker MCP Gateway","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"docker","product":"mcp-gateway","versions":[{"version":">= 0.21.0, < 0.42.2","status":"affected"}]}],"references":[{"url":"https://github.com/docker/mcp-gateway/security/advisories/GHSA-r2xf-7jw5-pjg6","name":"https://github.com/docker/mcp-gateway/security/advisories/GHSA-r2xf-7jw5-pjg6","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/docker/mcp-gateway/pull/498","name":"https://github.com/docker/mcp-gateway/pull/498","tags":["x_refsource_MISC"]},{"url":"https://github.com/docker/mcp-gateway/commit/306d2d94a3b526f43281313321bf784f2d46a7fe","name":"https://github.com/docker/mcp-gateway/commit/306d2d94a3b526f43281313321bf784f2d46a7fe","tags":["x_refsource_MISC"]},{"url":"https://github.com/docker/mcp-gateway/commit/439b2200d9e26a4ff414aeb043785df45a78422b","name":"https://github.com/docker/mcp-gateway/commit/439b2200d9e26a4ff414aeb043785df45a78422b","tags":["x_refsource_MISC"]},{"url":"https://github.com/docker/mcp-gateway/releases/tag/v0.42.2","name":"https://github.com/docker/mcp-gateway/releases/tag/v0.42.2","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"ACTIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","subAvailabilityImpact":"HIGH","baseScore":8.7,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-88","lang":"en","description":"CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-15T15:45:36.420Z"},"source":{"advisory":"GHSA-r2xf-7jw5-pjg6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-15T17:45:43.530044Z","id":"CVE-2026-55887","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-15T18:02:09.186Z"}}]}}}