CVE-2020-27534 is a medium-severity (CVSS 5.3) Path Traversal vulnerability in github.com/moby/moby. A fix is available for github.com/moby/moby — see the affected versions and patch details below.
Path Traversal in Moby builder
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/moby/moby🐹github.com/docker/dockerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
util/binfmt_misc/check.go in Builder in Docker Engine before 19.03.9 calls os.OpenFile with a potentially unsafe qemu-check temporary pathname, constructed with an empty first argument in an ioutil.TempDir call.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/moby/moby | all versions | 19.03.9go get github.com/moby/moby@v19.03.9 |
| 🐹Go | github.com/docker/docker | all versions | 19.03.9go get github.com/docker/docker@v19.03.9 |
Affected Products
dockerdockerDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/moby/moby, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/moby/moby to 19.03.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-27534 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2020-27534 in your dependencies?
Find it across Go, including transitive dependencies.