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Report · Zero Day InitiativeAbout CVE-2026-55887Published

ZDI-26-363: Docker MCP Plugin OCI Image Label Parsing Argument Injection Remote Code Execution Vulnerability

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Authoritative record:CVE-2026-55887· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 0.42.2 soon.

Data as of 7 Nov 2026, 23:24 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.42.2
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.

What to do

Upgrade mcp-gateway to 0.42.2.

Affected software

ProductAffectedFixed in
dockermcp-gatewayAffected
  • >=0.21.0 <0.42.2
Fixed in
  • 0.42.2

AI-suggested

Docker has issued an official security update to remediate this vulnerability. Users should apply the update provided by Docker as detailed in the advisory at https://github.com/docker/mcp-gateway/security/advisories/GHSA-r2xf-7jw5-pjg6. Applying this update mitigates the risk of exploitation.

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.

References

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