CVE-2026-68432

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

vxlan: require CAP_NET_ADMIN in the device netns for changelink

A tunnel changelink() operates on at most two netns, dev_net(dev) and

the sticky underlay netns vxlan->net. They differ once the device is

created in or moved to a netns other than the one the request runs in.

The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev),

so a caller privileged there but not in vxlan->net can rewrite a vxlan

device whose underlay lives in vxlan->net.

vxlan_changelink() validates and applies the new configuration against

vxlan->net (vxlan_config_validate(vxlan->net, ...)) and can reopen the

underlay socket in that netns, so the same reasoning as the tunnel

changelink series applies here.

Gate vxlan_changelink() with rtnl_dev_link_net_capable(), at the top of

the op before any attribute is parsed, matching ipgre_changelink() and

the rest of the "require CAP_NET_ADMIN in the device netns for

changelink" series.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References