What is CVE-2021-20291?

CVE-2021-20291 is a medium-severity uncontrolled resource consumption vulnerability in github.com/containers/storage (go), affecting versions < 1.28.1. It is fixed in 1.28.1. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.

How severe is CVE-2021-20291?

CVE-2021-20291 has a CVSS score of 6.5 (Medium). 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 versions of github.com/containers/storage are affected by CVE-2021-20291?

github.com/containers/storage (go) versions < 1.28.1 is affected.

Is there a fix for CVE-2021-20291?

Yes. CVE-2021-20291 is fixed in 1.28.1. Upgrade to this version or later.

Is CVE-2021-20291 exploitable, and should I be worried?

Whether CVE-2021-20291 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.

What actually determines whether CVE-2021-20291 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.

CVE-2021-20291 in github.com/containers/storage

Q: How severe is CVE-2021-20291?

CVE-2021-20291 has a CVSS score of 6.5 (Medium). 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.

Q: Which versions of github.com/containers/storage are affected by CVE-2021-20291?

github.com/containers/storage (go) versions < 1.28.1 is affected.

Q: Is there a fix for CVE-2021-20291?

Yes. CVE-2021-20291 is fixed in 1.28.1. Upgrade to this version or later.

Q: Is CVE-2021-20291 exploitable, and should I be worried?

Whether CVE-2021-20291 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.

Q: What actually determines whether CVE-2021-20291 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.

Q: How do I fix CVE-2021-20291?

Upgrade github.com/containers/storage to 1.28.1 or later.

Summary

Improper Locking in github.com/containers/storage

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).

Impact

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2021-20291 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no 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 (1.28.1); upgrading removes the vulnerable code path.

Affected versions

github.com/containers/storage (< 1.28.1)

Security releases

github.com/containers/storage → 1.28.1 (go)

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.

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Remediation advice

Upgrade github.com/containers/storage to 1.28.1 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2021-20291? CVE-2021-20291 is a medium-severity uncontrolled resource consumption vulnerability in github.com/containers/storage (go), affecting versions < 1.28.1. It is fixed in 1.28.1. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
How severe is CVE-2021-20291? CVE-2021-20291 has a CVSS score of 6.5 (Medium). 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 versions of github.com/containers/storage are affected by CVE-2021-20291? github.com/containers/storage (go) versions < 1.28.1 is affected.
Is there a fix for CVE-2021-20291? Yes. CVE-2021-20291 is fixed in 1.28.1. Upgrade to this version or later.
Is CVE-2021-20291 exploitable, and should I be worried? Whether CVE-2021-20291 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-2021-20291 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-2021-20291? Upgrade github.com/containers/storage to 1.28.1 or later.