Open Virtual Network (OVN) EUVD-2026-25421

Monitor Red Hat security portal (https://access.redhat.com/security/cve/CVE-2026-5367) and upstream OVN project for patch announcements following the April 20, 2026 oss-security disclosure. Red Hat Bugzilla 2455863 (https://bugzilla.redhat.com/show_bug.cgi?id=2455863) tracks the vendor fix and should provide patched package versions when available. Until patches are released, organizations can implement network-layer compensating controls: restrict DHCPv6 client access to OVN DHCPv6 servers using ACLs or security groups, limiting exposure to trusted network segments only - this reduces attack surface but impacts legitimate DHCPv6 functionality. In multi-tenant environments, consider temporarily disabling DHCPv6 in favor of static IPv6 addressing or DHCPv4-only configurations if operationally feasible, though this requires coordinated reconfiguration of virtual machine networking. Deploy network monitoring to detect anomalous DHCPv6 traffic patterns (oversized client identifiers, unusual DUID formats) as a detection control, though sophisticated attackers may evade signature-based detection. These workarounds carry operational complexity and should be replaced with vendor patches as soon as available.