CVE-2016-4955

Publication date 4 July 2016

Last updated 25 August 2025

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

5.9 · Medium

Score breakdown

Description

ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause a denial of service (peer-variable clearing and association outage) by sending (1) a spoofed crypto-NAK packet or (2) a packet with an incorrect MAC value at a certain time.

Status

Package Ubuntu Release Status
ntp 17.04 zesty
Not affected
16.10 yakkety
Not affected
16.04 LTS xenial
Fixed 1:4.2.8p4+dfsg-3ubuntu5.3
15.10 wily Ignored end of life
14.04 LTS trusty
Fixed 1:4.2.6.p5+dfsg-3ubuntu2.14.04.10
12.04 LTS precise
Fixed 1:4.2.6.p3+dfsg-1ubuntu3.11

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
ntp

Severity score breakdown

Parameter Value
Base score 5.9 · Medium
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

Other references