Vulnerability-Lookup

ubuntu-cve-2026-34956

Vulnerability from osv_ubuntu

Published

2026-05-05 16:16

Modified

2026-06-09 11:07

Summary

Details

A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath, a remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characters. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system.

Severity

5.9 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-34956	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-34956	REPORT
	https://www.openwall.com/lists/oss-security/2026/…	REPORT
	https://mail.openvswitch.org/pipermail/ovs-dev/20…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "openvswitch-common",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "openvswitch-pki",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "openvswitch-switch",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "openvswitch-switch-dpdk",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "openvswitch-test",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "openvswitch-testcontroller",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "openvswitch-vtep",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "ovn-central",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "ovn-common",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "ovn-controller-vtep",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "ovn-docker",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "ovn-host",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "python-openvswitch",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          },
          {
            "binary_name": "python3-openvswitch",
            "binary_version": "2.9.8-0ubuntu0.18.04.5+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "openvswitch",
        "purl": "pkg:deb/ubuntu/openvswitch@2.9.8-0ubuntu0.18.04.5+esm1?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
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        "2.8.1-0ubuntu2",
        "2.8.1-0ubuntu3",
        "2.9.0~git20180205.5a39582ca-0ubuntu1",
        "2.9.0-0ubuntu1",
        "2.9.2-0ubuntu0.18.04.2",
        "2.9.2-0ubuntu0.18.04.3",
        "2.9.5-0ubuntu0.18.04.1",
        "2.9.7-0ubuntu0.18.04.2",
        "2.9.8-0ubuntu0.18.04.2",
        "2.9.8-0ubuntu0.18.04.3",
        "2.9.8-0ubuntu0.18.04.4",
        "2.9.8-0ubuntu0.18.04.5",
        "2.9.8-0ubuntu0.18.04.5+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
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            "binary_version": "2.13.8-0ubuntu1.4"
          },
          {
            "binary_name": "openvswitch-pki",
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          {
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          {
            "binary_name": "openvswitch-switch-dpdk",
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          },
          {
            "binary_name": "openvswitch-test",
            "binary_version": "2.13.8-0ubuntu1.4"
          },
          {
            "binary_name": "openvswitch-testcontroller",
            "binary_version": "2.13.8-0ubuntu1.4"
          },
          {
            "binary_name": "openvswitch-vtep",
            "binary_version": "2.13.8-0ubuntu1.4"
          },
          {
            "binary_name": "python3-openvswitch",
            "binary_version": "2.13.8-0ubuntu1.4"
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        ]
      },
      "package": {
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        "name": "openvswitch",
        "purl": "pkg:deb/ubuntu/openvswitch@2.13.8-0ubuntu1.4?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
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          ],
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        }
      ],
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        "2.12.0-0ubuntu2",
        "2.12.1~git20191107.7accd1302-0ubuntu1",
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        "2.12.90~git20200107.af683565b-0ubuntu2",
        "2.12.90~git20200107.af683565b-0ubuntu3",
        "2.13.0~git20200127.dbdf66c29-0ubuntu2",
        "2.13.0~git20200212.15ae9db33-0ubuntu1",
        "2.13.0~git20200212.15ae9db33-0ubuntu2",
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        "2.13.1-0ubuntu0.20.04.1",
        "2.13.1-0ubuntu0.20.04.3",
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        "2.13.3-0ubuntu0.20.04.1",
        "2.13.3-0ubuntu0.20.04.2",
        "2.13.5-0ubuntu1",
        "2.13.8-0ubuntu1",
        "2.13.8-0ubuntu1.1",
        "2.13.8-0ubuntu1.2",
        "2.13.8-0ubuntu1.3",
        "2.13.8-0ubuntu1.4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "openvswitch-common",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-ipsec",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-pki",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-source",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-switch",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-switch-dpdk",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-test",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-testcontroller",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "openvswitch-vtep",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "python3-openvswitch",
            "binary_version": "2.17.9-0ubuntu0.22.04.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "openvswitch",
        "purl": "pkg:deb/ubuntu/openvswitch@2.17.9-0ubuntu0.22.04.2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.16.0-0ubuntu2",
        "2.16.0-0ubuntu3",
        "2.16.0-0ubuntu4",
        "2.17.0~git20220105.0d1ffb7-0ubuntu1",
        "2.17.0~git20220118.1b9fd88-0ubuntu1",
        "2.17.0~git20220121.109d024-0ubuntu1",
        "2.17.0-0ubuntu1",
        "2.17.2-0ubuntu0.22.04.1",
        "2.17.2-0ubuntu0.22.04.2",
        "2.17.3-0ubuntu0.22.04.1",
        "2.17.3-0ubuntu0.22.04.2",
        "2.17.5-0ubuntu0.22.04.2",
        "2.17.7-0ubuntu0.22.04.1",
        "2.17.8-0ubuntu0.22.04.1",
        "2.17.9-0ubuntu0.22.04.1",
        "2.17.9-0ubuntu0.22.04.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "openvswitch-common",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-ipsec",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-pki",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-source",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-switch",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-switch-dpdk",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-test",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-testcontroller",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "openvswitch-vtep",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          },
          {
            "binary_name": "python3-openvswitch",
            "binary_version": "3.3.4-0ubuntu0.24.04.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "openvswitch",
        "purl": "pkg:deb/ubuntu/openvswitch@3.3.4-0ubuntu0.24.04.2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.0-1",
        "3.2.0-2",
        "3.2.0-2build1",
        "3.2.2~git20231029-2",
        "3.2.2~git20231029-2build1",
        "3.3.0~git20240118.e802fe7-2",
        "3.3.0~git20240118.e802fe7-3",
        "3.3.0-1",
        "3.3.0-1build1",
        "3.3.0-1ubuntu1",
        "3.3.0-1ubuntu3",
        "3.3.0-1ubuntu3.1",
        "3.3.0-1ubuntu3.2",
        "3.3.4-0ubuntu0.24.04.1",
        "3.3.4-0ubuntu0.24.04.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "openvswitch-common",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-ipsec",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-pki",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-source",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-switch",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-switch-dpdk",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-test",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-testcontroller",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "openvswitch-vtep",
            "binary_version": "3.6.0-2ubuntu0.1"
          },
          {
            "binary_name": "python3-openvswitch",
            "binary_version": "3.6.0-2ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "openvswitch",
        "purl": "pkg:deb/ubuntu/openvswitch@3.6.0-2ubuntu0.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5.0-1build1",
        "3.5.1-0ubuntu1",
        "3.6.0-1",
        "3.6.0-2",
        "3.6.0-2ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "openvswitch-common",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-ipsec",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-pki",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-source",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-switch",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-switch-dpdk",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-test",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-testcontroller",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "openvswitch-vtep",
            "binary_version": "3.7.1-2"
          },
          {
            "binary_name": "python3-openvswitch",
            "binary_version": "3.7.1-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "openvswitch",
        "purl": "pkg:deb/ubuntu/openvswitch@3.7.1-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.6.0-2",
        "3.6.0-2build1",
        "3.6.0-5",
        "3.6.0-6",
        "3.6.0-6build1",
        "3.6.0-6ubuntu2",
        "3.7.0~git20260211.8c6ebf8-1~1.gbp9127d1",
        "3.7.0-1",
        "3.7.0-1build1",
        "3.7.1-1",
        "3.7.1-2"
      ]
    }
  ],
  "aliases": [],
  "details": "A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath, a remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characters. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system.",
  "id": "UBUNTU-CVE-2026-34956",
  "modified": "2026-06-09T11:07:38Z",
  "published": "2026-05-05T16:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34956"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34956"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2026/03/31/15"
    },
    {
      "type": "REPORT",
      "url": "https://mail.openvswitch.org/pipermail/ovs-dev/2026-March/431425.html"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-34956"
  ]
}

CVE-2026-34956 (GCVE-0-2026-34956)

Vulnerability from cvelistv5 – Published: 2026-05-05 15:45 – Updated: 2026-05-06 14:17

Title

Openvswitch: open vswitch: denial of service via malformed ftp epasv command

Summary

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Assigner

redhat

References

3 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-34956	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2453459	issue-trackingx_refsource_REDHAT
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

9 products

Vendor	Product	Version
Red Hat	Fast Datapath for RHEL 7	cpe:/o:redhat:enterprise_linux:7::fastdatapath
Red Hat	Fast Datapath for RHEL 8	cpe:/o:redhat:enterprise_linux:8::fastdatapath
Red Hat	Fast Datapath for RHEL 9	cpe:/o:redhat:enterprise_linux:9::fastdatapath
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
Red Hat	Red Hat OpenShift Container Platform 4	cpe:/a:redhat:openshift:4
Red Hat	Red Hat OpenStack Platform 13 (Queens)	cpe:/a:redhat:openstack:13
Red Hat	Red Hat OpenStack Platform 16.2	cpe:/a:redhat:openstack:16.2
Red Hat	Red Hat OpenStack Platform 17.1	cpe:/a:redhat:openstack:17.1
Red Hat	Red Hat OpenStack Platform 18.0	cpe:/a:redhat:openstack:18.0

Date Public

2026-03-31 00:00

Credits

Red Hat would like to thank Seiji Sakurai for reporting this issue.

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

ubuntu-cve-2026-34956

Vulnerability from osv_ubuntu

CVE-2026-34956 (GCVE-0-2026-34956)

Tags

Sightings

Nomenclature