CVE-2016-4957

Publication date 5 July 2016

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
ntp	16.04 LTS xenial	Not affected
	15.10 wily	Ignored end of life
	14.04 LTS trusty	Not affected
	12.04 LTS precise	Not affected

How can I get the fixes?
What do statuses mean?

Notes

mdeslaur

incorrect fix for CVE-2016-1547 redhat's fix for CVE-2016-1547 doesn't introduce this issue Ubuntu uses redhat's fix

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

MITRE
NVD
Launchpad
Debian

Other references

http://support.ntp.org/bin/view/Main/SecurityNotice#June_2016_ntp_4_2_8p8_NTP_Securi
https://www.cve.org/CVERecord?id=CVE-2016-4957