ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-1547.
CVE-2016-4957
Score elevated to 7.9 because EPSS predicts 45% probability of exploitation within the next 30 days (top 1.3% of all CVEs). NVD baseline CVSS 7.5 retained for reference. Confidence: see factors.
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.9(high)
- EG Risk
- 58(Track)EG Risk 58/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity79% × 45%Exploitation45% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 98.6%
- KEV
- Not listed
Published
July 5, 2016
Last Modified
May 6, 2026
References (26)
- cve@mitrehttp://bugs.ntp.org/3046
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.html
- cve@mitrehttp://support.ntp.org/bin/view/Main/NtpBug3046
- cve@mitrehttp://support.ntp.org/bin/view/Main/SecurityNotice
- cve@mitrehttp://www.kb.cert.org/vuls/id/321640
- cve@mitrehttp://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- cve@mitrehttp://www.securitytracker.com/id/1036037
- cve@mitrehttps://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.asc
- cve@mitrehttps://security.gentoo.org/glsa/201607-15
- af854a3a-2127-422b-91ae-364da2661108http://bugs.ntp.org/3046
- af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html
Data Freshness Timeline
(refreshed 10× in last 7d / 35× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 14:14 UTCEPSS rescore
- 2026-07-23 01:23 UTCEG score recompute▲ 0.40
- 2026-07-22 22:02 UTCEG score recompute
- 2026-07-22 14:04 UTCEPSS rescore
- 2026-07-21 15:21 UTCEPSS rescore
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- 2026-07-16 16:59 UTCEPSS rescore
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- 2026-07-15 16:54 UTCEPSS rescore
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- 2026-07-13 22:26 UTCEPSS rescore
- 2026-07-13 06:09 UTCEPSS rescore
- 2026-07-12 09:07 UTCOSV refresh
- 2026-07-12 05:43 UTCEPSS rescore
- 2026-07-12 05:43 UTCEPSS rescore
- 2026-07-11 08:23 UTCEPSS rescore
- 2026-07-09 19:05 UTCEPSS rescore
- 2026-07-08 15:10 UTCEPSS rescore
- 2026-07-06 16:24 UTCEPSS rescore
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- 2026-07-06 16:24 UTCEPSS rescore
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- 2026-06-25 13:47 UTCEPSS rescore
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- 2026-06-24 14:02 UTCEPSS rescore
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- 2026-06-23 21:30 UTCEPSS rescore
- 2026-06-23 14:30 UTCOSV refresh
- 2026-06-22 14:23 UTCEPSS rescore
- 2026-06-21 14:54 UTCEPSS rescore
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- 2026-06-10 22:15 UTCEPSS rescore
- 2026-06-08 14:14 UTCEPSS rescore
- 2026-06-06 17:59 UTCOSV refresh
- 2026-06-06 13:45 UTCEPSS rescore
- 2026-06-05 22:44 UTCEPSS rescore
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- 2026-05-27 13:38 UTCEPSS rescore
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- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:16 UTCEPSS rescore
- 2026-05-24 16:43 UTCEPSS rescore
- 2026-05-22 21:15 UTCEPSS rescore
- 2026-05-22 21:15 UTCEPSS rescore
- 2026-05-22 19:43 UTCEG score recompute
- 2026-05-22 19:43 UTCGHSA enrichment
- 2026-05-21 22:40 UTCEPSS rescore
- 2026-05-20 22:37 UTCEPSS rescore
- 2026-05-20 22:37 UTCEPSS rescore
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- 2026-05-18 21:30 UTCEPSS rescore
- 2026-05-18 21:30 UTCEPSS rescore
Frequently asked(5)
What is CVE-2016-4957?
When was CVE-2016-4957 disclosed?
Is CVE-2016-4957 actively exploited?
What is the CVSS score of CVE-2016-4957?
How do I remediate CVE-2016-4957?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2016-4957
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