CVE-2026-46120

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ip6_gre: Use cached t-&gt;net in ip6erspan_changelink().<br /> <br /> After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of<br /> rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns<br /> ip6gre hash via link_net. ip6erspan_changelink() was not converted in<br /> that series and still uses dev_net(dev), which diverges from the<br /> device&amp;#39;s creation netns after IFLA_NET_NS_FD migration.<br /> <br /> This re-inserts the tunnel into the wrong per-netns hash. The<br /> original netns keeps a stale entry. When that netns is later<br /> destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a<br /> slab-use-after-free reported by KASAN, followed by a kernel BUG at<br /> net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify().<br /> <br /> Reachable from an unprivileged user namespace (unshare --user<br /> --map-root-user --net).<br /> <br /> ip6gre_changelink() earlier in the same file already uses the cached<br /> t-&gt;net; only ip6erspan_changelink() has the wrong shape.