Bug 2464093 (CVE-2026-31692)

Summary: CVE-2026-31692 kernel: rtnetlink: add missing netlink_ns_capable() check for peer netns
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-04-30 12:01:30 UTC 
In the Linux kernel, the following vulnerability has been resolved:

rtnetlink: add missing netlink_ns_capable() check for peer netns

rtnl_newlink() lacks a CAP_NET_ADMIN capability check on the peer
network namespace when creating paired devices (veth, vxcan,
netkit). This allows an unprivileged user with a user namespace
to create interfaces in arbitrary network namespaces, including
init_net.

Add a netlink_ns_capable() check for CAP_NET_ADMIN in the peer
namespace before allowing device creation to proceed.
Comment 1 Keith Grant 2026-05-01 14:44:15 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026043054-CVE-2026-31692-5f89@gregkh/T