CVE-2026-31692

A flaw was found in the Linux kernel's rtnetlink component. An unprivileged local user, leveraging a user namespace, can exploit a missing CAP_NET_ADMIN capability check in the rtnl_newlink() function. This allows the user to create paired network devices in arbitrary network namespaces, including the init_net (initial network namespace). Such unauthorized creation of network interfaces could lead to unexpected network configurations and potential system instability or resource exhaustion.

This vulnerability is rated Moderate because exploitation requires local access and the ability to create unprivileged user namespaces, limiting the blast radius to unauthorized creation of virtual interfaces across namespaces rather than direct arbitrary code execution. On typical Red Hat Enterprise Linux installations where unprivileged user namespaces are enabled, a local attacker can create paired network interfaces inside arbitrary namespaces, potentially causing resource consumption or network disruption. The issue cannot be triggered remotely and does not directly lead to kernel memory corruption or elevated root privileges on the host.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.