CVE-2026-68142geneve: require CAP_NET_ADMIN in the device netns for changelink

Official description

In the Linux kernel, the following vulnerability has been resolved: geneve: 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 geneve->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 geneve->net can rewrite a geneve device whose underlay lives in geneve->net. geneve_changelink() applies the new configuration against geneve->net: geneve_link_config() and the geneve_quiesce()/geneve_unquiesce() pair reopen the underlay sockets in that netns (geneve_sock_add() uses geneve->net), so the same reasoning as the tunnel changelink series applies here. Gate geneve_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. Found by 0sec automated security-research tooling (https://0sec.ai).

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/a5522963c57f12df5f9db804ebfc472b58eef0ae
• https://git.kernel.org/stable/c/278c6a31ee27c931c722202c8c06cc3253923254
• https://git.kernel.org/stable/c/11a7d989d00160481a273eb4f7f05f64b5a6ffdf
• https://git.kernel.org/stable/c/2abdacc927c92fa6a9cc8341e8c9b88dcb561553
• https://git.kernel.org/stable/c/9de5518fc1fab583526a8f66b8e505c4864dc60a
• https://git.kernel.org/stable/c/f8c498585d2a08aa623748353c3e61467b7e9fd2
• https://git.kernel.org/stable/c/95f45e20f1b2cec13823f0f68060ab4b2261b2c1
• https://git.kernel.org/stable/c/8efb8f8bbb353b8f2fdf4f37534c6d96c9f69e01