CVE-2021-21285: Moby Docker Daemon Crash during Image Pull
Summary
CVE-2021-21285: moby docker daemon crash during image pull of malicious image. Affects github.com/moby/moby across 2 version ranges.
< 19.3.15
>= 20.10.0-beta1, < 20.10.3
Fixed in 19.3.15 or 20.10.3, depending on the release line you run. How to fix ↓
Also tracked for
- docker.io · Debian:11
The same CVE-2021-21285 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Moby is an open-source project that provides a platform for building, packaging, and distributing containerized applications. It includes the Docker daemon (dockerd), which is responsible for managing Docker containers. The vulnerability (CVE-2021-21285) affects the Moby project's Docker daemon and can lead to a crash when pulling a maliciously crafted Docker image manifest.
Vulnerability Detail
The vulnerability arises when the Docker daemon attempts to pull a Docker image with an intentionally malformed manifest. This triggers a crash in the dockerd daemon, disrupting the normal operation of the containerization system. The impact of this vulnerability is limited to a denial-of-service (DoS) scenario, as it causes the Docker daemon to crash and requires manual intervention to restart it. The vulnerability has been assigned a CVSS score of 6.5, indicating a moderate severity level.
How To Fix
Latest published version: v28.5.2+incompatible as of 23 Oct 2026
go get github.com/moby/moby@v28.5.2+incompatibleUpgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 19.3.1519.3.15go get github.com/moby/moby@v19.3.15 -
>= 20.10.0-beta1, < 20.10.320.10.3go get github.com/moby/moby@v20.10.3
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
There is no specific workaround mentioned for this vulnerability. However, applying the recommended fix by updating to the patched versions is the best course of action.
Conclusion
The vulnerability (CVE-2021-21285) in the Moby project's Docker daemon can lead to a crash when pulling a malicious Docker image manifest. To mitigate this vulnerability, it is crucial to update the Docker daemon to versions 20.10.3 or 19.03.15. These versions contain patches that prevent the daemon from crashing. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for github.com/moby/moby →
FAQ
The vulnerability causes the Docker daemon to crash when pulling a malicious Docker image manifest, resulting in a denial-of-service (DoS) scenario.
The vulnerability can disrupt the normal operation of the containerization system, requiring manual intervention to restart the Docker daemon.
Versions prior to 19.03.15 and 20.10.3 are affected by this vulnerability.
Updating the Docker daemon to versions 20.10.3 or 19.03.15 will address this vulnerability.
No specific workaround is mentioned. Updating to the patched versions is the recommended solution.
References
Related vulnerabilities
Recent vulnerabilities recorded for github.com/moby/moby.
