CVE-2026-46120
Description
In the Linux kernel, the following vulnerability has been resolved: ip6_gre: Use cached t->net in ip6erspan_changelink(). After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns ip6gre hash via link_net. ip6erspan_changelink() was not converted in that series and still uses dev_net(dev), which diverges from the device's creation netns after IFLA_NET_NS_FD migration. This re-inserts the tunnel into the wrong per-netns hash. The original netns keeps a stale entry. When that netns is later destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a slab-use-after-free reported by KASAN, followed by a kernel BUG at net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify(). Reachable from an unprivileged user namespace (unshare --user --map-root-user --net). ip6gre_changelink() earlier in the same file already uses the cached t->net; only ip6erspan_changelink() has the wrong shape.
How to fix
- linux linux_kernel4.17, 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 4.16.12 ≤ v < 4.17, 4.17.1 ≤ v < 5.10.258, 5.11 ≤ v < 5.15.209, 5.16 ≤ v < 6.1.175, 6.2 ≤ v < 6.6.140, 6.7 ≤ v < 6.12.88, 6.13 ≤ v < 6.18.30, 6.19 ≤ v < 7.0.7, 4.17, 7.1 | 4.17, 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7 |
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