# CVE-2021-20267: neutron-common: A flaw was found in openstack-neutron's default Open vSwitch firewall rules

CVE-2021-20267 is fixed in 17 products on 1 platform, first by neutron-common 2:12.1.1-0ubuntu8.1, released March 6, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-20267
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0104
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 28, 2021

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | neutron-common Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-common 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-common-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-common Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-common 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-common-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-dhcp-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-dhcp-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-dhcp-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-dhcp-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-dhcp-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-dhcp-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-l3-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-l3-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-l3-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-l3-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-l3-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-l3-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-linuxbridge-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-linuxbridge-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-linuxbridge-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-linuxbridge-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-linuxbridge-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-linuxbridge-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-macvtap-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-macvtap-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-macvtap-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-macvtap-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-macvtap-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-macvtap-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-metadata-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-metadata-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-metadata-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-metadata-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-metadata-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-metadata-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-metering-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-metering-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-metering-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-metering-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-metering-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-metering-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-openvswitch-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-openvswitch-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-openvswitch-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-openvswitch-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-openvswitch-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-openvswitch-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-ovn-metadata-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-ovn-metadata-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-ovn-metadata-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-plugin-linuxbridge-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-plugin-linuxbridge-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-plugin-linuxbridge-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-plugin-ml2 Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-plugin-ml2 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-plugin-ml2-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-plugin-ml2 Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-plugin-ml2 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-plugin-ml2-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-plugin-openvswitch-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-plugin-openvswitch-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-plugin-openvswitch-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-plugin-sriov-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-plugin-sriov-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-plugin-sriov-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-server Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-server 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-server-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-server Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-server 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-server-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | neutron-sriov-agent Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [neutron-sriov-agent 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-neutron-sriov-agent-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | neutron-sriov-agent Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [neutron-sriov-agent 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-neutron-sriov-agent-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |
| Linux | python-neutron Ubuntu 18.04.6 LTS (bionic) | 2:12.1.1-0ubuntu8.1 | [python-neutron 2:12.1.1-0ubuntu8.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-neutron-2-12.1.1-0ubuntu8.1.md) | Mar 6, 2023 |
| Linux | python3-neutron Ubuntu 20.04 LTS (focal) | 2:16.4.2-0ubuntu6.2 | [python3-neutron 2:16.4.2-0ubuntu6.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-neutron-2-16.4.2-0ubuntu6.2.md) | Mar 6, 2023 |

---

Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.