CVE-2026-34956 Details
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.
A heap access vulnerability has been identified in Open vSwitch. This issue arises when Open vSwitch is set up with a conntrack flow using FTP helpers over the userspace datapath. A remote attacker can exploit this by sending a crafted FTP stream containing an EPASV command that exceeds 255 characters. This exploitation causes a heap access error, which can crash the system, leading to a denial-of-service condition.
Users can optionally avoid using FTP flows, as these are not typically configured by default. Red Hat users should refer to the Red Hat Security Errata for their specific version for guidance on applying the fix.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 6, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-120 | Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') | [email protected] |
Affected Products
No affected product data is available for this CVE.
Change History
8 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 1, 2026 | CVE Modified | [email protected] |
| Aug 31, 2026 | CVE Modified | [email protected] |
| Aug 31, 2026 | CVE Modified | CVE |
| Aug 21, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 5, 2026 | CVE Modified | CVE |
| May 5, 2026 | New CVE Received | [email protected] |