CVE-2014-0021: Chrony before 1.29.1 has traffic amplification in cmdmon protocol

Q: How do I fix CVE-2014-0021?

chrony: upgrade to 1.29; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2014-0021 being exploited?

CVE-2014-0021 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2014-0021 affect?

CVE-2014-0021 affects chrony, debian linux, fedora. Severity is high (CVSS 7.5). Chrony before 1.29.1 has traffic amplification in cmdmon protocol

Q: How urgent is CVE-2014-0021?

Priority 59/100. High severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2014-0021 is a high-severity flaw (CVSS 7.5) affecting chrony, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Chrony before 1.29.1 has traffic amplification in cmdmon protocol

Why this priority

High severity
EPSS top 9%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	4.2% (top 9%)
CISA exploited list	No
Published	2019-11-15
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: chrony project · debian · fedoraproject

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-11-15 15:15 UTCPublished CVE record published
2026-06-17 00:02 UTCUpdated Record last modified

chrony project chrony UPGRADE

Affected: < 1.29

Fixed in: 1.29

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy chrony || rpm -q chrony || chrony --version

2. UPGRADE to 1.29 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade chrony

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade chrony

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fedoraproject fedora MITIGATE

Affected: 19 · 20

Fixed in: no fixed release known

Safe to downgrade to: a release before 19

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2014-0021?

chrony: upgrade to 1.29; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2014-0021 being exploited?

CVE-2014-0021 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2014-0021 affect?

CVE-2014-0021 affects chrony, debian linux, fedora. Severity is high (CVSS 7.5). Chrony before 1.29.1 has traffic amplification in cmdmon protocol

How urgent is CVE-2014-0021?

Priority 59/100. High severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2020-14367 MEDIUM 6.0 UPGRADE MITIGATE A flaw was found in chrony versions before 3.5.1 when creating the PID file under the /var/run/chrony folder
CVE-2015-1853 MEDIUM 6.5 UPGRADE chrony before 1.31.1 does not properly protect state variables in authenticated symmetric NTP associations, wh

References

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