How severe is CVE-2021-20319?

CVE-2021-20319 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-20319?

CVE-2021-20319 affects the following packages: coreos-installer (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2021-20319?

Update coreos-installer to 0.10.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-20319 is resolved across your whole dependency graph.

How do I detect CVE-2021-20319 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for coreos-installer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-20319 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-20319 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-20319 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-20319?

CVE-2021-20319 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-20319?

CVE-2021-20319 is classified as CWE-347 (CWE-347). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-20319 published, and has it been updated?

CVE-2021-20319 was published on March 4, 2022 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

HIGH severity

CVE-2021-20319 — coreos-installer

HIGHFix: coreos/coreos-installer#659

CVE-2021-20319 is a high-severity (CVSS 7.8) CWE-347 vulnerability in coreos-installer. A fix is available for coreos-installer — see the affected versions and patch details below.

coreos-installer improperly verifies GPG signature when decompressing gzipped artifact

Also known asGHSA-3r3g-g73x-g593RUSTSEC-2022-0103

Published

Mar 4, 2022

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-20319 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🦀coreos-installer

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Impact

coreos-installer fails to correctly verify GPG signatures when decompressing gzip-compressed artifacts. This allows bypass of signature verification in cases where coreos-installer decompresses a downloaded OS image, allowing an attacker who can modify the OS image to compromise a newly-installed system.

Default installations from ISO or PXE media in Fedora CoreOS, RHEL CoreOS, and RHEL for Edge are not affected, as coreos-installer installs from an OS image shipped as part of the install media.

These flows are affected:

Installing with --image-file, --image-url, or coreos.inst.image_url. For example, if a user has a local mirror of installation images, an attacker could replace an image with a gzip-compressed alternative (even if the file extension is .xz). The result:

$ coreos-installer install --image-url http://localhost:8080/image.xz /dev/loop0
Downloading image from http://localhost:8080/image.xz
Downloading signature from http://localhost:8080/image.xz.sig
> Read disk 749.9 MiB/749.9 MiB (100%)
gpg: Signature made Mon 20 Sep 2021 02:41:50 PM EDT
gpg: using RSA key 8C5BA6990BDB26E19F2A1A801161AE6945719A39
gpg: BAD signature from "Fedora (34) <[email protected]>" [ultimate]
Install complete.

Notice that GPG reports a bad signature, but coreos-installer continues anyway. Automation that relies on coreos-installer's exit status will not notice either.

coreos-installer download --decompress --image-url:

$ coreos-installer download --decompress --image-url http://localhost:8080/image.xz
> Read disk 749.9 MiB/749.9 MiB (100%)
gpg: Signature made Mon 20 Sep 2021 02:41:50 PM EDT
gpg: using RSA key 8C5BA6990BDB26E19F2A1A801161AE6945719A39
gpg: BAD signature from "Fedora (34) <[email protected]>" [ultimate]
./image

Again, coreos-installer reports success.

Installing with default parameters, when not installing from the image built into live ISO or PXE media, if the hosting service is compromised or if an active attacker gains control of the HTTPS response.
coreos-installer download --decompress if the hosting service is compromised or if an active attacker gains control of the HTTPS response.

Patches

The vulnerability is fixed in coreos-installer 0.10.1.

Workarounds

For coreos-installer download, do not use the -d or --decompress options.

For coreos-installer install, manually inspect the stderr output. If BAD signature appears, do not boot from the target disk. Note, however, that some OS services may have already accessed data on the compromised disk.

References

For more information, see PR 655.

For more information

If you have any questions or comments about this advisory, open an issue in coreos-installer or email the CoreOS development mailing list.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`coreos-installer`	all versions	0.10.1`cargo update -p coreos-installer --precise 0.10.1`

Affected Products

1 product · 1 configurations

Application

coreos-installerredhat

< 0.10.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for coreos-installer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update coreos-installer to 0.10.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-20319 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

This vulnerability impacts only a specific User-Provisioned Infrastructure (UPI) installation flow where coreos-installer is used and when gzip-compressed images are configured as the installation source. Because this flow does not occur in default usage, Red Hat considers this case as a Moderate impact flaw.

Product	Fixed in	Advisory
Red Hat OpenShift Container Platform 4.10	`coreos-installer-0:0.12.0-1.rhaos4.10.el8`	RHSA-2022:0055
Red Hat OpenShift Container Platform 4.6	`coreos-installer-0:0.6.0-4.rhaos4.6.el8`	RHSA-2021:4008
Red Hat OpenShift Container Platform 4.7	`coreos-installer-0:0.8.0-4.rhaos4.7.el8`	RHSA-2021:3930
Red Hat OpenShift Container Platform 4.8	`coreos-installer-0:0.9.0-7.rhaos4.8.el8`	RHSA-2021:3926
Red Hat OpenShift Container Platform 4.9	`coreos-installer-0:0.10.1-1.rhaos4.9.el8`	RHSA-2021:3934

Frequently Asked Questions

### Impact coreos-installer fails to correctly verify GPG signatures when decompressing gzip-compressed artifacts. This allows bypass of signature verification in cases where coreos-installer decompresses a downloaded OS image, allowing an attacker who can modify the OS image to compromise a newly-installed system. Default installations from ISO or PXE media in Fedora CoreOS, RHEL CoreOS, and RHEL for Edge are **not** affected, as coreos-installer installs from an OS image shipped as part of the install media. These flows are affected: 1. Installing with `--image-file`, `--image-url`, or