CVE-2015-1853

Publication date 9 December 2019

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

chrony before 1.31.1 does not properly protect state variables in authenticated symmetric NTP associations, which allows remote attackers with knowledge of NTP peering to cause a denial of service (inability to synchronize) via random timestamps in crafted NTP data packets.

From the Ubuntu Security Team

Miroslav Lichvár discovered a head-based buffer overflow in chrony. A remote attacker could use this vulnerability to cause a denial of service (crash) or execute arbitrary code.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
chrony	18.10 cosmic	Not affected
	18.04 LTS bionic	Not affected
	17.10 artful	Not affected
	17.04 zesty	Ignored end of life
	16.10 yakkety	Ignored end of life
	16.04 LTS xenial	Not affected
	15.10 wily	Ignored end of life
	15.04 vivid	Ignored end of life
	14.10 utopic	Ignored end of life
	14.04 LTS trusty	Fixed 1.29-1ubuntu0.1
	12.04 LTS precise	Ignored end of life
	10.04 LTS lucid	Ignored end of life

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.5 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	None
Integrity impact	None
Availability impact	High

Scores

Parameter	Value
Base score	6.5 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H