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PatchSiren cyber security CVE debrief

CVE-2026-34956 Red Hat CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-05-05T16:16:11.927Z and has not been modified since then. Open vSwitch has a flaw that can cause a Denial of Service (DoS) condition. A remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characters, triggering a heap access error and resulting in a crash. System administrators and security teams should review the official advisory or CVE record to validate affected scope, severity, and vendor guidance. They should assess potential impact and prioritize defensive actions accordingly.

Vendor
Red Hat
Product
Fast Datapath for RHEL 7
CVSS
MEDIUM 5.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-05
Original CVE updated
2026-08-21
Advisory published
2026-05-05
Advisory updated
2026-08-21

Who should care

System administrators and security teams responsible for Open vSwitch installations should be aware of this potential vulnerability. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Affected operator, platform, vulnerability-management, and security-team impact should be assessed to prioritize defensive actions.

Technical summary

A flaw in Open vSwitch can cause a Denial of Service (DoS) condition when a specially crafted FTP stream is sent to the system. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system. The vulnerability is triggered when Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath. The issue arises from improper handling of FTP commands, specifically the EPASV command, which can exceed 255 characters. This can lead to a system crash and potential disruption of service. Open vSwitch installations should be reviewed for potential exposure, and defensive actions should be prioritized to mitigate the risk of a Denial of Service (DoS) attack.

Defensive priority

Medium-priority defensive actions are recommended due to the potential for Denial of Service (DoS) attacks.

Recommended defensive actions

  • Inventory and verify Open vSwitch installations
  • Implement compensating controls to detect and prevent potential DoS attacks
  • Monitor system logs for suspicious activity
  • Apply vendor patches when available
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

Evidence from the NVD and Red Hat sources indicates a potential Denial of Service (DoS) vulnerability in Open vSwitch. However, detailed information about the vulnerability is limited. The CVE record was published on 2026-05-05T16:16:11.927Z and has not been modified since then. Additional verification tasks are recommended to confirm affected product deployments and assess potential exposure.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-05-05T16:16:11.927Z and has not been modified since then.