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CVE-2021-20267

Published: 28 May 2021

A flaw was found in openstack-neutron's default Open vSwitch firewall rules. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the IPv6 addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations. Only deployments using the Open vSwitch driver are affected. Source: OpenStack project. Versions before openstack-neutron 15.3.3, openstack-neutron 16.3.1 and openstack-neutron 17.1.1 are affected.

Notes

AuthorNote
mdeslaur
per upstream Affects: <15.3.3, >=16.0.0 <16.3.1, >=17.0.0 <17.1.1
as of 2021-05-13, patch has been flagged as possibly incomplete
see comment #17 in upstream bug.
addditional patch: https://review.opendev.org/c/openstack/neutron/+/783743

This issue was fixed in (2:16.4.0-0ubuntu2) in focal-updates and
(2:18.1.0-0ubuntu2) in hirsute-updates, and was later
released to -security.

Priority

Medium

Cvss 3 Severity Score

7.1

Score breakdown

Status

Package Release Status
neutron
Launchpad, Ubuntu, Debian
bionic
Released (2:12.1.1-0ubuntu8.1)
focal
Released (2:16.4.2-0ubuntu6.2)
groovy Ignored
(end of life)
hirsute Ignored
(end of life)
impish Not vulnerable
(2:18.1.0+git2021072117.147830620f-0ubuntu2)
jammy Not vulnerable
(2:18.1.0+git2021072117.147830620f-0ubuntu2)
kinetic Not vulnerable
(2:18.1.0+git2021072117.147830620f-0ubuntu2)
lunar Not vulnerable
(2:18.1.0+git2021072117.147830620f-0ubuntu2)
mantic Not vulnerable
(2:18.1.0+git2021072117.147830620f-0ubuntu2)
trusty Does not exist

upstream
Released (15.3.3,16.3.1,17.1.1)
xenial Needed

Patches:
upstream: https://opendev.org/openstack/neutron/commit/580e57b2ad07d268067b2043fd1f5b33bd8f785e
upstream: https://opendev.org/openstack/neutron/commit/ac474307d3a800c30ecbabf0f47de931ad310339
upstream: https://opendev.org/openstack/neutron/commit/7b1f0dd1aed68f98b5472c2dfa821e9338f286f0
upstream: https://opendev.org/openstack/neutron/commit/ccea0021bc49eefde9af6568942159b52588daae

Severity score breakdown

Parameter Value
Base score 7.1
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality Low
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H