The process_packet function in ntp_proto.c in ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (peer-variable modification) by sending spoofed packets from many source IP addresses in a certain scenario, as demonstrated by triggering an incorrect leap indication.
CVE-2016-4954
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. NVD baseline CVSS 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 54(Track)EG Risk 54/100SSVC: 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 computedSeverity75% × 45%Exploitation40% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 13%
- EPSS %ILE
- 96%
- KEV
- Not listed
Published
July 5, 2016
Last Modified
June 17, 2026
References (70)
- cve@mitrehttp://bugs.ntp.org/3044
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-06/msg00020.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://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
- cve@mitrehttp://packetstormsecurity.com/files/137321/Slackware-Security-Advisory-ntp-Updates.html
- cve@mitrehttp://packetstormsecurity.com/files/137322/FreeBSD-Security-Advisory-FreeBSD-SA-16-24.ntp.html
- cve@mitrehttp://support.ntp.org/bin/view/Main/NtpBug3044
- cve@mitrehttp://support.ntp.org/bin/view/Main/SecurityNotice
- cve@mitrehttp://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160603-ntpd
- cve@mitrehttp://www.kb.cert.org/vuls/id/321640
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | ntpdate (1:4.2.6.p5+dfsg-3ubuntu2.14.04.10) @ trusty | 2026-05-22 | ubuntu |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| ntp | — | 1:4.2.8p8+dfsg-1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 5× in last 7d / 18× 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.
Showing the most recent 100 of 133 total refreshes for this CVE.
- 2026-09-19 15:35 UTCEPSS rescore
- 2026-09-18 23:23 UTCOSV refresh
- 2026-09-18 19:22 UTCEPSS rescore
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- 2026-08-11 13:36 UTCEPSS rescore
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- 2026-07-23 01:23 UTCEG score recompute
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- 2026-07-22 14:04 UTCEPSS rescore
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- 2026-07-13 22:26 UTCEPSS rescore
- 2026-07-12 09:07 UTCOSV refresh
- 2026-07-12 05:43 UTCEPSS rescore
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- 2026-06-25 13:47 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 01:57 UTCEPSS rescore
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- 2026-06-18 17:50 UTCEPSS rescore
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- 2026-06-07 15:22 UTCEPSS rescore
- 2026-06-06 17:59 UTCOSV refresh
- 2026-06-06 13:45 UTCEPSS rescore
Frequently asked(5)
What is CVE-2016-4954?
When was CVE-2016-4954 disclosed?
Is CVE-2016-4954 actively exploited?
What is the CVSS score of CVE-2016-4954?
How do I remediate CVE-2016-4954?
Dependency Blast Radius
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