CVE-2021-40085

Publication date 31 August 2021

Last updated 18 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An issue was discovered in OpenStack Neutron before 16.4.1, 17.x before 17.2.1, and 18.x before 18.1.1. Authenticated attackers can reconfigure dnsmasq via a crafted extra_dhcp_opts value.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
neutron	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Ignored end of life
	20.04 LTS focal	Fixed 2:16.4.2-0ubuntu6.2
	18.04 LTS bionic	Fixed 2:12.1.1-0ubuntu8.1
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Not in release

Notes

mdeslaur

This issue was fixed in (2:16.4.1-0ubuntu2) in focal-updates and (2:18.1.1-0ubuntu2) in hirsute-updates, and was later released to -security.

Patch details

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

Package	Patch details
neutron	Upstream: 110fed0

Severity score breakdown

Parameter	Value
Base score	6.5 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N