CVE-2021-20291: A deadlock vulnerability was found in 'github.com/containers/storage' in versions before 1.28.1. When a container image is processed, each layer is un...

Description

A deadlock vulnerability was found in 'github.com/containers/storage' in versions before 1.28.1. When a container image is processed, each layer is unpacked using `tar`. If one of those layers is not a valid `tar` archive this causes an error leading to an unexpected situation where the code indefinitely waits for the tar unpacked stream, which never finishes. An attacker could use this vulnerability to craft a malicious image, which when downloaded and stored by an application using containers/storage, would then cause a deadlock leading to a Denial of Service (DoS).

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

1.59%

72.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-667

Affected Software

Vendor	Product	Versions
Storage Project	Storage	< 1.28.1
Redhat	Openshift Container Platform	4.0
Redhat	Enterprise Linux	8.0
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34

References

Timeline

Published: Apr 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20291?

A deadlock vulnerability was found in 'github.com/containers/storage' in versions before 1.28.1. When a container image is processed, each layer is unpacked using `tar`. If one of those layers is not a valid `tar` archive this causes an error leading to an unexpected situation where the code indefinitely waits for the tar unpacked stream, which never finishes. An attacker could use this vulnerability to craft a malicious image, which when downloaded and stored by an application using containers/storage, would then cause a deadlock leading to a Denial of Service (DoS).

How severe is CVE-2021-20291?

CVE-2021-20291 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.59% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20291?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.