Summary
When a user uploads a compressed archive into a container, a malicious image can execute arbitrary code with daemon (host root) privileges.
Details
When handling PUT /containers/{id}/archive requests with compressed archives, the daemon decompresses them using external system binaries. Due to incorrect ordering of operations, these binaries are resolved from the container's filesystem rather than the host's. A container image that includes a trojanized decompression binary can achieve code execution as the daemon process whenever a compressed archive is uploaded to that container.
The executed binary runs with the daemon's full privileges, including host root UID and unrestricted capabilities.
Conditions for exploitation
- A user must run a container from a malicious image that contains a trojanized decompression binary.
- The user must then upload a compressed archive (xz or gzip) into that container, either by piping a compressed archive via
docker cp -or by calling thePUT /containers/{id}/archiveAPI directly with compressed content.
Not affected
Standard docker cp usage is not affected, because the CLI sends uncompressed tar by default:
docker cp ./file.txt mycontainer:/file.txt
This can only be exploited when explicitly passing a xz or gzip-compressed archive to docker cp or the PUT /containers/{id}/archive API, for example:
cat archive.tar.xz | docker cp - mycontainer:/dir
Decompression formats using pure Go implementations (bzip2, zstd, and gzip when the container image does not contain an unpigz binary) are also not affected.
Workarounds
- Only run containers from trusted images.
- Use authorization plugins to limit access to the
PUT /containers/{id}/archiveendpoint. - Avoid piping compressed archives into containers created from untrusted images.
Impact
Arbitrary code execution as host root, crossing the container-to-host trust boundary.
CVE-2026-41567 has a CVSS score of 7.2 (High). The vector is requires local access, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.0-beta.14); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-41567? CVE-2026-41567 is a high-severity security vulnerability in github.com/moby/moby/v2 (go), affecting versions < 2.0.0-beta.14. It is fixed in 2.0.0-beta.14.
- How severe is CVE-2026-41567? CVE-2026-41567 has a CVSS score of 7.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-41567?
github.com/moby/moby/v2(go) (versions < 2.0.0-beta.14)github.com/docker/docker(go) (versions <= 28.5.2)github.com/moby/moby(go) (versions <= 28.5.2)
- Is there a fix for CVE-2026-41567? Yes. CVE-2026-41567 is fixed in 2.0.0-beta.14. Upgrade to this version or later.
- Is CVE-2026-41567 exploitable, and should I be worried? Whether CVE-2026-41567 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-41567 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-41567? Upgrade
github.com/moby/moby/v2to 2.0.0-beta.14 or later.