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neutron — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-20267

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.

Products
neutron
Affected versions
Not specified
Fixed versions
2:17.1.1-5
CVEs
CVE-2021-20267
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 23:59 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-20267

core-osv · Original source

Published 28 May 2021, 19:15 UTC

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.

osv:DEBIAN-CVE-2021-20267

neutron

Fixed versions: 2:17.1.1-5

neutron

Fixed versions: 2:17.1.1-5

neutron

Fixed versions: 2:17.1.1-5

Complete source record
{
  "id": "29cdebcbe15a6808679d819ae575d098d7575b6df2344505e84f88b1dd0ad35c",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-20267",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-20267",
    "summary": "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.",
    "evidence": "osv:DEBIAN-CVE-2021-20267",
    "products": [
      {
        "name": {
          "value": "neutron",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2:17.1.1-5",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "neutron",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2:17.1.1-5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "neutron",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2:17.1.1-5",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-20267",
      "aliases": [
        "DEBIAN-CVE-2021-20267"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2:17.1.1-5"
                }
              ]
            }
          ],
          "package": {
            "name": "neutron",
            "purl": "pkg:deb/debian/neutron?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-20267.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2:17.1.1-5"
                }
              ]
            }
          ],
          "package": {
            "name": "neutron",
            "purl": "pkg:deb/debian/neutron?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-20267.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2:17.1.1-5"
                }
              ]
            }
          ],
          "package": {
            "name": "neutron",
            "purl": "pkg:deb/debian/neutron?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-20267.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:02:41.032859108Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-20267"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-20267"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-20267",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 419620,
  "published_at": "2021-05-28T19:15:07.483+00:00"
}