Denial of Service Vulnerability in Open vSwitch Affected by FTP Command
CVE-2026-34956

5.9MEDIUM

Key Information:

Vendor

Red Hat
Status
Fast Datapath For Rhel 7
Fast Datapath For Rhel 8
Fast Datapath For Rhel 9
Red Hat Enterprise Linux 7
Vendor
CVE Published:
5 May 2026

What is CVE-2026-34956?

A vulnerability exists in Open vSwitch that affects systems configured with conntrack flow using FTP helpers over the userspace datapath. By sending a specially crafted FTP stream containing an EPASV command with a length exceeding 255 characters, a remote attacker could trigger a heap access error. This flaw can subsequently lead to system crashes, resulting in Denial of Service for the impacted environment. Appropriate measures should be taken to secure affected systems against this potential attack vector.

References

https://access.redhat.com/security/cve/CVE-2026-34956
vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2453459
issue-trackingx_refsource_REDHAT

CVSS V3.1

Score:
5.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

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