CVE-2026-33997: Moby Plugin Privilege Validation Bypass Vulnerability
Summary
CVE-2026-33997: Moby has an Off-by-one error in its plugin privilege validation. Affected versions are not published. No fix is published. How to fix ↓
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Background
Moby is an open-source project that provides a framework for building container-based applications. It includes the Docker Engine, which allows users to create, manage, and deploy containers. Moby supports plugins that extend its functionality, enabling users to customize their container environments. However, a recent vulnerability has been identified in the plugin privilege validation process, which could allow malicious plugins to bypass security measures.
Vulnerability Detail
The vulnerability arises from an off-by-one error in the privilege validation logic during the installation of Docker plugins. When a plugin is installed, the Docker daemon checks the privileges requested by the plugin against those approved by the user. Due to the error, the daemon may incorrectly accept a privilege set that does not match the user's approval. This flaw particularly affects plugins that request exactly one privilege, as no comparison is performed in those cases. The potential ramifications include unauthorized access to sensitive resources, especially if a malicious plugin is installed from an untrusted source.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
If you cannot update immediately, consider the following workarounds: 1. Do not install plugins from untrusted sources. 2. Carefully review all privileges requested during 'docker plugin install'. 3. Restrict access to the Docker daemon to trusted parties, following the principle of least privilege. 4. Avoid relying solely on plugin privilege approval as a security control in sensitive environments.
Conclusion
The CVE-2026-33997 vulnerability in Moby presents a significant risk due to the potential for unauthorized access through malicious plugins. Users are advised to update to the latest versions of the affected packages and implement the recommended workarounds to mitigate risks until a full update can be applied.
See every vulnerability recorded for github.com/docker/docker →
FAQ
CVE-2026-33997 is a vulnerability in Moby that allows for the bypass of plugin privilege validation during installation, potentially leading to unauthorized access.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which monitors open-source vulnerabilities without requiring sign-up.
The risks include unauthorized access to sensitive resources and potential exploitation by malicious plugins, especially if installed from untrusted sources.
If immediate updates are not possible, avoid installing plugins from untrusted sources and review all requested privileges carefully.
The CVSS score of this vulnerability is 6.8, indicating a moderate level of severity.
References
Related vulnerabilities
Recent vulnerabilities recorded for github.com/docker/docker.
