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MEDIUM

CVE-2021-20291

CVSS v3

6.5

MEDIUM

EPSS Score

1.6 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • github.com/containers/storageGoall versions · fixed in 1.28.1
  • buildahAlmaLinux:9all versions · fixed in 1:1.27.0-2.el9and 1 other package
  • critAlmaLinux:8all versions · fixed in 3.15-3.module_el8.6.0+2877+8e437bf5
  • criuAlmaLinux:8all versions · fixed in 3.15-3.module_el8.6.0+2751+06427ca3and 2 other packages
  • criu-develAlmaLinux:8all versions · fixed in 3.15-3.module_el8.5.0+2613+1b78b731
  • libslirpAlmaLinux:8all versions · fixed in 4.4.0-1.module_el8.5.0+2613+1b78b731
  • libslirp-develAlmaLinux:8all versions · fixed in 4.4.0-1.module_el8.6.0+2877+8e437bf5
  • oci-seccomp-bpf-hookAlmaLinux:8all versions · fixed in 1.2.3-3.module_el8.5.0+2613+1b78b731

5 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-20291 Red Hat Product Security934 products fixed · 6 known affected

    containers/storage: DoS via malicious image

    buildah.src as a component of Red Hat Enterprise Linux 7 · podman.src as a component of Red Hat Enterprise Linux 7 · skopeo.src as a component of Red Hat Enterprise Linux 7

  • RHSA-2022:8008 Red Hat Product Security21 products fixed

    Red Hat Security Advisory: buildah security and bug fix update

  • RHSA-2022:7954 Red Hat Product Security46 products fixed

    Red Hat Security Advisory: podman security and bug fix update

  • RHSA-2022:7955 Red Hat Product Security17 products fixed

    Red Hat Security Advisory: skopeo security and bug fix update

  • RHBA-2022:0348 Red Hat Product Security236 products fixed

    Red Hat Bug Fix Advisory: container-tools:3.0 security, bug fix, and enhancement update

  • RHSA-2021:4154 Red Hat Product Security256 products fixed

    Red Hat Security Advisory: container-tools:rhel8 security, bug fix, and enhancement update

3 more advisories

Full record on NVD

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).

Technical details

Published
2021-04-01

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).

Is CVE-2021-20291 actively exploited?

Active exploitation of CVE-2021-20291 has not been confirmed. Its EPSS score was 1.6% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20291?

CVE-2021-20291 has a CVSS v3 base score of 6.5 (MEDIUM severity).

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