CVE-2026-31692
Description
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.
Statement
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.1 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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