# CVE-2021-20291: Improper Locking in github.com/containers/storage > An attacker can cause a Denial of Service by crafting a malicious container image that triggers a deadlock in the containers/storage library during layer unpacking. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 1 Apr 2021 - **Updated:** 3 Aug 2024 - **Also known as:** ALBA-2022:0348, AZL-44580, DEBIAN-CVE-2021-20291, GHSA-7qw8-847f-pggm, GO-2021-0100, RHBA-2022:0348, RHSA-2021:1150, UBUNTU-CVE-2021-20291 ## What is CVE-2021-20291? CVE-2021-20291 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 1 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official 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). Weakness: CWE-667 (Improper Locking) ## Which versions are affected by CVE-2021-20291? 3 open source packages ship an affected version, including github.com/containers/storage. It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/containers/storage` | Go | All versions | 1.28.1 | | `github.com/containers/storage` | Go | All versions | 1.28.1 | | `github.com/containers/storage` | Go | All versions | 1.28.1 | | `buildah` | AlmaLinux:8 | All versions | 1.19.9-1.module_el8.5.0+2614+87221ce8 | | `buildah-tests` | AlmaLinux:8 | All versions | 1.19.9-1.module_el8.5.0+2614+87221ce8 | | `cockpit-podman` | AlmaLinux:8 | All versions | 29-2.module_el8.5.0+2614+87221ce8 | | `cockpit-podman` | AlmaLinux:8 | All versions | 29-2.module_el8.6.0+2876+9ed4eae2 | | `conmon` | AlmaLinux:8 | All versions | 2:2.0.26-1.module_el8.5.0+2614+87221ce8 | | `conmon` | AlmaLinux:8 | All versions | 2:2.0.26-1.module_el8.6.0+2876+9ed4eae2 | | `container-selinux` | AlmaLinux:8 | All versions | 2:2.167.0-1.module_el8.5.0+2614+87221ce8 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 0.9.1-1.module_el8.5.0+2614+87221ce8 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 0.9.1-1.module_el8.6.0+2876+9ed4eae2 | | `containers-common` | AlmaLinux:8 | All versions | 1:1.2.4-1.module_el8.5.0+2614+87221ce8 | | `containers-common` | AlmaLinux:8 | All versions | 1:1.2.4-1.module_el8.6.0+2876+9ed4eae2 | | `crit` | AlmaLinux:8 | All versions | 3.15-1.module_el8.5.0+2614+87221ce8 | | `crit` | AlmaLinux:8 | All versions | 3.15-1.module_el8.6.0+2876+9ed4eae2 | | `criu` | AlmaLinux:8 | All versions | 3.15-1.module_el8.5.0+2614+87221ce8 | | `criu` | AlmaLinux:8 | All versions | 3.15-1.module_el8.6.0+2876+9ed4eae2 | | `crun` | AlmaLinux:8 | All versions | 0.18-2.module_el8.5.0+2614+87221ce8 | | `fuse-overlayfs` | AlmaLinux:8 | All versions | 1.4.0-2.module_el8.5.0+2614+87221ce8 | | `fuse-overlayfs` | AlmaLinux:8 | All versions | 1.4.0-2.module_el8.6.0+2876+9ed4eae2 | | `libslirp` | AlmaLinux:8 | All versions | 4.3.1-1.module_el8.5.0+2614+87221ce8 | | `libslirp` | AlmaLinux:8 | All versions | 4.3.1-1.module_el8.6.0+2876+9ed4eae2 | | `libslirp-devel` | AlmaLinux:8 | All versions | 4.3.1-1.module_el8.5.0+2614+87221ce8 | | `libslirp-devel` | AlmaLinux:8 | All versions | 4.3.1-1.module_el8.6.0+2876+9ed4eae2 | | `oci-seccomp-bpf-hook` | AlmaLinux:8 | All versions | 1.2.0-3.module_el8.5.0+2614+87221ce8 | | `oci-seccomp-bpf-hook` | AlmaLinux:8 | All versions | 1.2.0-3.module_el8.6.0+2876+9ed4eae2 | | `podman` | AlmaLinux:8 | All versions | 3.0.1-7.module_el8.5.0+2614+87221ce8 | | `podman-catatonit` | AlmaLinux:8 | All versions | 3.0.1-7.module_el8.5.0+2614+87221ce8 | | `podman-docker` | AlmaLinux:8 | All versions | 3.0.1-7.module_el8.5.0+2614+87221ce8 | | `podman-plugins` | AlmaLinux:8 | All versions | 3.0.1-7.module_el8.5.0+2614+87221ce8 | | `podman-remote` | AlmaLinux:8 | All versions | 3.0.1-7.module_el8.5.0+2614+87221ce8 | | `podman-tests` | AlmaLinux:8 | All versions | 3.0.1-7.module_el8.5.0+2614+87221ce8 | | `python3-criu` | AlmaLinux:8 | All versions | 3.15-1.module_el8.5.0+2614+87221ce8 | | `python3-criu` | AlmaLinux:8 | All versions | 3.15-1.module_el8.6.0+2876+9ed4eae2 | | `runc` | AlmaLinux:8 | All versions | 1.0.0-72.rc92.module_el8.5.0+2614+87221ce8 | | `skopeo` | AlmaLinux:8 | All versions | 1:1.2.4-1.module_el8.5.0+2614+87221ce8 | | `skopeo` | AlmaLinux:8 | All versions | 1:1.2.4-1.module_el8.6.0+2876+9ed4eae2 | | `skopeo-tests` | AlmaLinux:8 | All versions | 1:1.2.4-1.module_el8.5.0+2614+87221ce8 | | `skopeo-tests` | AlmaLinux:8 | All versions | 1:1.2.4-1.module_el8.6.0+2876+9ed4eae2 | Products: Fedoraproject Fedora, Redhat Enterprise Linux, Redhat Openshift Container Platform, Storage Project Storage. ## How do I fix CVE-2021-20291? Upgrade github.com/containers/storage to 1.28.1 or later. ## Is CVE-2021-20291 being exploited? There is no known exploitation of CVE-2021-20291 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-20291 and fix it if it is affected. What it is: CVE-2021-20291 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 1 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2021-20291 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/containers/storage (Go): affected all versions; fixed in 1.28.1 - github.com/containers/storage (Go): affected all versions; fixed in 1.28.1 - github.com/containers/storage (Go): affected all versions; fixed in 1.28.1 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2021-20291/ (Markdown: https://insights.sbomify.com/CVE-2021-20291/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20291 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20291 - OSV: https://osv.dev/vulnerability/CVE-2021-20291 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-20291/ Summaries are generated and may contain mistakes; the official description above is the record.