Logic Flaw in LXC Container Runtime Affects OpenVSwitch Network Interfaces

CVE-2026-39402

What is CVE-2026-39402?

The LXC container runtime exhibits a logic flaw within the setuid helper, lxc-user-nic, allowing unprivileged users to delete network interfaces attached to OpenVSwitch (OVS) ports owned by other users. This occurs due to inadequate authorization checks in the find_line() function responsible for validating deletion requests. When an unprivileged attacker sends a deletion request, the system may erroneously grant authorization based solely on interface name matches, neglecting critical checks for ownership and type. This vulnerability primarily impacts multi-tenant environments, wherein one tenant can disrupt service for other users by disconnecting their networking capabilities on shared infrastructure. The issue is resolved in version 7.0.0.

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