MCP Gateway: Argument injection via OCI image label YAML in Docker MCP Gateway

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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.

Source published

15 Sep 2026 15:45:36 UTC

Source modified

15 Sep 2026 18:02:09 UTC

Saved here

23 Oct 2026 15:48:27 UTC

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CVE Program Terms of Use

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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

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.

Source published

Sep 15, 2026, 3:45:36 PM (timezone not stated)

Source modified

Sep 15, 2026, 6:02:09 PM (timezone not stated)

Saved here

11 Nov 2026 14:05:12 UTC

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ENISA EUVD · source terms and attribution apply

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EUVD 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

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.

Source published

15 Sep 2026 16:17:16 UTC

Source modified

30 Sep 2026 17:51:56 UTC

Saved here

25 Oct 2026 14:19:05 UTC

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NIST NVD usage terms; underlying source attribution retained

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CVSS 4.0 · [email protected] · Secondary · 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

## Summary A maliciously crafted OCI image label can inject arbitrary arguments into the `docker run` command line constructed by the MCP Gateway. An attacker who controls an image that the victim references via `docker://`, or that the victim's catalog pulls a snapshot from, can mount the host filesystem, run as UID 0, and execute arbitrary code on the host. ## Details The `io.docker.server.metadata` OCI image label is YAML-unmarshalled directly into the wide `catalog.Server` struct, which carries runtime-shaping fields (`Volumes`, `User`, `Command`, `ExtraHosts`, `AllowHosts`, `DisableNetwork`, `Env`, `Remote`, `SSEEndpoint`, `OAuth`,`Secrets`, `LongLived`, `Policy`) alongside descriptive fields. Every runtime field carries a YAML tag, so the unmarshal mass-assigns from the attacker-controlled label content; only `Image` is overwritten afterwards. The gateway's container-launch code then appends those fields verbatim as `docker run` flags (`-v`, `-u`, `--add-host`) with no allowlist or origin check, and execs `docker` with the resulting argv. ## Impact A malicious image author can achieve arbitrary code execution as UID 0 on the host of a victim running an affected version of MCP Gateway. Attacker-injected `-v /:/host`, `-u root`, and `-v /var/run/docker.sock:/var/run/docker.sock` arguments reach the `docker run` invocation that launches the MCP server container, giving the attacker full host filesystem access and root execution. The container/host trust boundary is bypassed at container-creation time, so the `--security-opt no-new-privileges` flag the gateway applies provides no protection: no in-container privilege escalation is needed. ## Patches The OCI image-label parser now only populates descriptive fields from the image label, which excludes fields that control the container runtime. ## Credit This issue was reported by Jabr Al-Otaibi `@ DarkCov` working with TrendAI Zero Day Initiative

Source published

18 Jun 2026 13:05:06 UTC

Source modified

25 Jun 2026 23:11:30 UTC

Saved here

24 Oct 2026 13:19:41 UTC

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GitHub Advisory Database · CC-BY-4.0

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Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V4 · 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

Publisher rating · HIGH

Docker MCP Gateway: Argument injection via OCI image label YAML in github.com/docker/mcp-gateway

Source published

25 Jun 2026 22:34:34 UTC

Source modified

25 Jun 2026 23:01:35 UTC

Saved here

24 Oct 2026 13:19:41 UTC

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OSV · upstream source license applies

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