CVE-2026-34956 PUBLISHED

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

Assigner: redhat
Reserved: 31.03.2026 Published: 05.05.2026 Updated: 05.05.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 5.9

Product Status

Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 7
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 8
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Fast Datapath for RHEL 9
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 7
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenShift Container Platform 4
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenShift Container Platform 4
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenShift Container Platform 4
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenShift Container Platform 4
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 13 (Queens)
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 13 (Queens)
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 13 (Queens)
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 16.2
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 16.2
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 17.1
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 17.1
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenStack Platform 18.0
Versions Default: affected

Workarounds

Optionally, avoid using alg=ftp flows. These are not usually configured.

Credits

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

References

Problem Types

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