CVE-2021-20319Public exploit

Node compromise via skipped GPG exit check

Published Mar 4, 2022 · Updated Aug 3, 2024

Improper signature verification in CoreOS coreos-installer before 0.10.1 allows attackers to install unsigned gzip-compressed images. The gzip decoder stops at its trailer without consuming source EOF, so the wrapped GPG reader never checks GPG's failing exit status. Exploitation requires control of a configured installation image source or its transport; default ISO and PXE installations using embedded images are unaffected, while affected flows grant full access to the new node.

CVSS severity7.8
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in CoreOS coreos-installer before 0.10.1 allows attackers to install unsigned gzip-compressed images. The gzip decoder stops at its trailer without consuming source EOF, so the wrapped GPG reader never checks GPG's failing exit status. Exploitation requires control of a configured installation image source or its transport; default ISO and PXE installations using embedded images are unaffected, while affected flows grant full access to the new node.

The record

CVE
CVE-2021-20319
Published
Mar 4, 2022
Updated
Aug 3, 2024
Vendor
CoreOS
Product
coreos-installer
Classifications
CWE-347, T1195.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Affects coreos-installer before v0.10.1, Fixed in v0.10.1.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

CoreOS · coreos-installerversion=Affects coreos-installer before v0.10.1, Fixed in v0.10.1.

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1195.002Compromise Software Supply Chain

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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