CVE-2020-27534 Path Traversal in Moby builder

What is CVE-2020-27534?

CVE-2020-27534 is a medium-severity path traversal vulnerability in n/a, published on 30 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-22

Which versions are affected by CVE-2020-27534?

4 open source packages ship an affected version, including github.com/docker/docker and github.com/moby/moby. It affects 1 product.

Products include Docker Docker.

How do I fix CVE-2020-27534?

Upgrade github.com/docker/docker to 19.03.9 or later.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2020-27534 being exploited?

There is no known exploitation of CVE-2020-27534 in the wild and no public exploit code.

Other vulnerabilities in n/a

• CVE-2014-9357 Arbitrary Code Execution Critical 10.0
• CVE-2020-14298 Privilege escalation in Docker High 8.8
• CVE-2020-14300 Privilege escalation in Docker High 8.8
• CVE-2018-15514 Deserialization in n/a High 8.8
• CVE-2014-9356 Path Traversal in Docker High 8.6

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6hwg-w5jg-9c6x.