Linux kernel ip6_gre/ip6erspan use-after-free in ip6erspan_changelink()
CVE-2026-46120 is a Linux kernel vulnerability in the ip6_gre subsystem, specifically in ip6erspan_changelink(). After commit 5e72ce3e3980 changed newlink() handling to use link_net for per-network-namespace resolution, ip6erspan_newlink() was updated accordingly, but ip6erspan_changelink() continued to use dev_net(dev) instead of the cached tunnel namespace pointer t->net. Following IFLA_NET_NS_FD-based network namespace migration, dev_net(dev) can differ from the tunnel's creation namespace. As a result, the tunnel can be reinserted into the wrong per-netns ip6gre hash while the original namespace retains a stale entry. When the original namespace is later torn down, ip6gre_exit_rtnl_net() may traverse that stale entry, leading to a KASAN-reported slab use-after-free and subsequently a kernel BUG in unregister_netdevice_many_notify() at net/core/dev.c involving LIST_POISON1.
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Recent activity
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Linux kernel vulnerability in Bluetooth virtio_bt receive length validation.
A Linux kernel vulnerability in ip6_gre/ip6erspan link change handling related to use of network context.
A Linux kernel vulnerability in ip6_gre/ip6erspan_changelink() caused by using dev_net(dev) instead of cached t->net, leading to stale per-network-namespace tunnel entries and a slab use-after-free/kernel BUG. The issue is reachable from an unprivileged user namespace.
Linux kernel vulnerability in ip6_gre/ip6erspan link change handling related to network namespace reference usage.
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