What’s Vulnerable › Vulnerabilities

CVE-2021-20291

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-04-01 · updated 2026-06-17
• Weakness: CWE-667

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).

Affected products

• Fedoraproject Fedora: 33, 34
• Red Hat Enterprise Linux: 8.0
• Red Hat OpenShift Container Platform 4.18: 4.0
• Storage Project Storage: before 1.28.1 — fixed in 1.28.1

How to fix

Upgrade to a fixed version: Storage Project Storage 1.28.1. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=1939485
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R5D7XL7FL24TWFMGQ3K2S72EOUSLZMKL/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPYOHNG2Q7DCAQZMGYLMENLKALGDLG3X/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WX24EITRXVHDM5M223BVTJA2ODF2FSHI/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNMB7O2UIXE34PGSCSOULGHPX5LIJBMM/
• https://unit42.paloaltonetworks.com/cve-2021-20291/
• https://bugzilla.redhat.com/show_bug.cgi?id=1939485
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R5D7XL7FL24TWFMGQ3K2S72EOUSLZMKL/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPYOHNG2Q7DCAQZMGYLMENLKALGDLG3X/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WX24EITRXVHDM5M223BVTJA2ODF2FSHI/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNMB7O2UIXE34PGSCSOULGHPX5LIJBMM/
• https://unit42.paloaltonetworks.com/cve-2021-20291/

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