Public vulnerability disclosure
CVE-2026-34956
Openvswitch: open vswitch: denial of service via malformed ftp epasv command
publishedCWE-120
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.
Technical severity5.9 mediumCVSS 3.1 · CNA: redhat
Published2026-05-05Source updated 2026-11-02
Collected2026-11-022 attributed sources
Fixes and workarounds
Workaround
Optionally, avoid using alg=ftp flows. These are not usually configured.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Fast Datapath for RHEL 7 Red Hat openvswitch
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat openvswitch2.10
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat openvswitch2.11
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat openvswitch2.12
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat openvswitch2.13
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat openvswitch-selinux-extra-policy
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat ovn2.11
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 7 Red Hat ovn2.12
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch2.11
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch2.12
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch2.13
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch2.15
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch2.16
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch2.17
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch3.1
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat openvswitch-selinux-extra-policy
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat ovn2.11
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 8 Red Hat ovn2.12
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch2.17
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.0
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.1
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.2
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.3
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.4
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.5
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch3.6
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Fast Datapath for RHEL 9 Red Hat openvswitch-selinux-extra-policy
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat openvswitch
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-8
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openvswitch2.17
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openvswitch3.0
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openvswitch3.1
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 13 (Queens) Red Hat rhosp13/openstack-neutron-openvswitch-agent
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 13 (Queens) Red Hat rhosp13/openstack-openvswitch-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 13 (Queens) Red Hat rhosp13/openstack-ovn-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 16.2 Red Hat rhosp-openvswitch
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 16.2 Red Hat rhosp-rhel8/openstack-neutron-openvswitch-agent
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 17.1 Red Hat rhosp-openvswitch
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 17.1 Red Hat rhosp-rhel9/openstack-neutron-openvswitch-agent
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenStack Platform 18.0 Red Hat rhoso-openvswitch
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 5.9 medium |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/security/cve/CVE-2026-34956CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2453459CNA: redhat · issue-tracking, x_refsource_REDHAT
- http://www.openwall.com/lists/oss-security/2026/03/31/15ADP: CVE