CVE-2026-34956

Publication date 5 May 2026

Last updated 13 May 2026

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
openvswitch	26.04 LTS resolute	Needs evaluation
	25.10 questing	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Not affected

Notes

mdeslaur

Per Debian, introduced in 2.9.0 by: https://github.com/openvswitch/ovs/commit/bd5e81a0e596dd012d11824cce69b7c80ae107c5

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
openvswitch	Upstream: 8e81545 Upstream: ba03a85 Upstream: 354afec Upstream: 1291c22 Upstream: a9785c7

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.9 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	None
Integrity impact	None
Availability impact	High

Scores

Parameter	Value
Base score	5.9 · Medium
Exploitability score	-
Impact score	-

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