{"id":"UBUNTU-CVE-2026-34956","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.","modified":"2026-08-13T07:45:12.009739888Z","published":"2026-05-05T16:16:00Z","upstream":["CVE-2026-34956"],"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"}],"affected":[{"package":{"name":"openvswitch","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/openvswitch?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.8.0-0ubuntu2","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":[{"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_version":"2.9.8-0ubuntu0.18.04.5+esm1","binary_name":"openvswitch-switch-dpdk"},{"binary_name":"openvswitch-test","binary_version":"2.9.8-0ubuntu0.18.04.5+esm1"},{"binary_version":"2.9.8-0ubuntu0.18.04.5+esm1","binary_name":"openvswitch-testcontroller"},{"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_version":"2.9.8-0ubuntu0.18.04.5+esm1","binary_name":"ovn-controller-vtep"},{"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_version":"2.9.8-0ubuntu0.18.04.5+esm1","binary_name":"python-openvswitch"},{"binary_name":"python3-openvswitch","binary_version":"2.9.8-0ubuntu0.18.04.5+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34956.json"}},{"package":{"name":"openvswitch","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/openvswitch?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.12.0-0ubuntu1","2.12.0-0ubuntu2","2.12.1~git20191107.7accd1302-0ubuntu1","2.12.90~git20200107.af683565b-0ubuntu1","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","2.13.0-0ubuntu1","2.13.1-0ubuntu0.20.04.1","2.13.1-0ubuntu0.20.04.3","2.13.1-0ubuntu0.20.04.4","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":"2.13.8-0ubuntu1.4"},{"binary_name":"openvswitch-pki","binary_version":"2.13.8-0ubuntu1.4"},{"binary_name":"openvswitch-source","binary_version":"2.13.8-0ubuntu1.4"},{"binary_name":"openvswitch-switch","binary_version":"2.13.8-0ubuntu1.4"},{"binary_name":"openvswitch-switch-dpdk","binary_version":"2.13.8-0ubuntu1.4"},{"binary_name":"openvswitch-test","binary_version":"2.13.8-0ubuntu1.4"},{"binary_version":"2.13.8-0ubuntu1.4","binary_name":"openvswitch-testcontroller"},{"binary_version":"2.13.8-0ubuntu1.4","binary_name":"openvswitch-vtep"},{"binary_name":"python3-openvswitch","binary_version":"2.13.8-0ubuntu1.4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34956.json"}},{"package":{"name":"openvswitch","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/openvswitch?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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","2.17.12-0ubuntu0.22.04.1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.17.12-0ubuntu0.22.04.1","binary_name":"openvswitch-common"},{"binary_name":"openvswitch-ipsec","binary_version":"2.17.12-0ubuntu0.22.04.1"},{"binary_name":"openvswitch-pki","binary_version":"2.17.12-0ubuntu0.22.04.1"},{"binary_version":"2.17.12-0ubuntu0.22.04.1","binary_name":"openvswitch-source"},{"binary_name":"openvswitch-switch","binary_version":"2.17.12-0ubuntu0.22.04.1"},{"binary_name":"openvswitch-switch-dpdk","binary_version":"2.17.12-0ubuntu0.22.04.1"},{"binary_name":"openvswitch-test","binary_version":"2.17.12-0ubuntu0.22.04.1"},{"binary_name":"openvswitch-testcontroller","binary_version":"2.17.12-0ubuntu0.22.04.1"},{"binary_version":"2.17.12-0ubuntu0.22.04.1","binary_name":"openvswitch-vtep"},{"binary_name":"python3-openvswitch","binary_version":"2.17.12-0ubuntu0.22.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34956.json"}},{"package":{"name":"openvswitch","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/openvswitch?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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","3.3.9-0ubuntu0.24.04.1"],"ecosystem_specific":{"binaries":[{"binary_name":"openvswitch-common","binary_version":"3.3.9-0ubuntu0.24.04.1"},{"binary_version":"3.3.9-0ubuntu0.24.04.1","binary_name":"openvswitch-ipsec"},{"binary_name":"openvswitch-pki","binary_version":"3.3.9-0ubuntu0.24.04.1"},{"binary_version":"3.3.9-0ubuntu0.24.04.1","binary_name":"openvswitch-source"},{"binary_name":"openvswitch-switch","binary_version":"3.3.9-0ubuntu0.24.04.1"},{"binary_name":"openvswitch-switch-dpdk","binary_version":"3.3.9-0ubuntu0.24.04.1"},{"binary_name":"openvswitch-test","binary_version":"3.3.9-0ubuntu0.24.04.1"},{"binary_name":"openvswitch-testcontroller","binary_version":"3.3.9-0ubuntu0.24.04.1"},{"binary_version":"3.3.9-0ubuntu0.24.04.1","binary_name":"openvswitch-vtep"},{"binary_name":"python3-openvswitch","binary_version":"3.3.9-0ubuntu0.24.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34956.json"}},{"package":{"name":"openvswitch","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/openvswitch?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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":"3.6.0-2ubuntu0.1"},{"binary_version":"3.6.0-2ubuntu0.1","binary_name":"openvswitch-ipsec"},{"binary_version":"3.6.0-2ubuntu0.1","binary_name":"openvswitch-pki"},{"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_version":"3.6.0-2ubuntu0.1","binary_name":"openvswitch-test"},{"binary_name":"openvswitch-testcontroller","binary_version":"3.6.0-2ubuntu0.1"},{"binary_version":"3.6.0-2ubuntu0.1","binary_name":"openvswitch-vtep"},{"binary_version":"3.6.0-2ubuntu0.1","binary_name":"python3-openvswitch"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34956.json"}},{"package":{"name":"openvswitch","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/openvswitch?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"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_version":"3.7.1-2","binary_name":"openvswitch-test"},{"binary_version":"3.7.1-2","binary_name":"openvswitch-testcontroller"},{"binary_name":"openvswitch-vtep","binary_version":"3.7.1-2"},{"binary_name":"python3-openvswitch","binary_version":"3.7.1-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34956.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}