CVE-2016-4953
ntp: bad authentication demobilizes ephemeral associations
Severity
LowRed Hat Product Security
CVSS 2.0
Review impact separately from score.
Published · June 2, 2016
Updated · November 21, 2025
Description
ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (ephemeral-association demobilization) by sending a spoofed crypto-NAK packet with incorrect authentication data at a certain time.
Statement
This issue did not affect the versions of ntp as shipped with any Red Hat Enterprise Linux version as they already included a fix for this issue in the patch provided to fix the CVE-2015-7979 issue. The fix for this issue (developed by Red Hat) was different from the one provided by upstream, and thus ntp versions in RHEL are not affected by CVE-2016-4953.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 2.0 · 2.6AV:N/AC:H/Au:N/C:N/I:N/A:P
CWE not specified