5.9

CVE-2026-34956: openvswitch Classic Buffer Overflow

CVSS: 5.9v3.1MediumAwaiting analysis
AliasesSUSE-SU-2026:1439-1SUSE-SU-2026:1440-1SUSE-SU-2026:1482-1
Published 05-05-2026Last modified 01-09-2026
Open JSON

Vulnerability summary

CVE-2026-34956 is a medium (CVSS 5.9) Classic Buffer Overflow vulnerability in openvswitch. EPSS estimates a 0.64% chance of exploitation in the next 30 days, higher than 49.7% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.64%
0%100%
Low · +0.23 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 3
OPENSUSE-SU-2026:20972-1SUSE-SU-2026:22145-1SUSE-SU-2026:22152-1

Timeline

  1. 05-05-2026
    PublishedVulnerability first disclosed.
  2. 01-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.64%

Chance of exploitation in the next 30 days

Percentile

50%

Versus all other CVEs

30-day change

+0.23 pp

From 0.40% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.64%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Suse6 products
  • openvswitch3&distro=SUSE Linux Enterprise Micro 5.5< 3.1.7-150500.3.28.1
  • openvswitch&distro=SUSE Linux Enterprise Module for Package Hub 15 SP7< 3.5.4-150700.41.15.1
  • openvswitch&distro=SUSE Linux Enterprise Module for Server Applications 15 SP7< 3.5.4-150700.41.15.1
  • openvswitch&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5< 2.11.5-3.30.1
  • openvswitch&distro=SUSE Linux Micro 6.0< 3.1.7-5.1
Debian1 product
  • openvswitchAll versions (No fix recorded) | < 3.7.1-1
Opensuse1 product
  • openvswitch&distro=openSUSE Tumbleweed< 3.7.1-33.1
Ubuntu1 product
  • openvswitchAll versions (No fix recorded)

4 vendors · 9 products

References

16 links
Show all 16 references