FKIE_CVE-2026-46120

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-05-28 13:44
Severity
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1d324c2f43f70c965f25c58cc3611c779adbe47e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/311fdd26eb4443d43b909cc67a10f3a5fd1b21b2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cf7fc624329e76c6394653d12353e1d033adea91
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/eca62bb0569de4d43a4dac06a2092a9d4ca1d702
Impacted products
Vendor Product Version
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nip6_gre: Use cached t-\u003enet in ip6erspan_changelink().\n\nAfter commit 5e72ce3e3980 (\"net: ipv6: Use link netns in newlink() of\nrtnl_link_ops\"), ip6erspan_newlink() correctly resolves the per-netns\nip6gre hash via link_net. ip6erspan_changelink() was not converted in\nthat series and still uses dev_net(dev), which diverges from the\ndevice\u0027s creation netns after IFLA_NET_NS_FD migration.\n\nThis re-inserts the tunnel into the wrong per-netns hash. The\noriginal netns keeps a stale entry. When that netns is later\ndestroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a\nslab-use-after-free reported by KASAN, followed by a kernel BUG at\nnet/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify().\n\nReachable from an unprivileged user namespace (unshare --user\n--map-root-user --net).\n\nip6gre_changelink() earlier in the same file already uses the cached\nt-\u003enet; only ip6erspan_changelink() has the wrong shape."
    }
  ],
  "id": "CVE-2026-46120",
  "lastModified": "2026-05-28T13:44:01.663",
  "metrics": {},
  "published": "2026-05-28T10:16:27.497",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1d324c2f43f70c965f25c58cc3611c779adbe47e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/311fdd26eb4443d43b909cc67a10f3a5fd1b21b2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cf7fc624329e76c6394653d12353e1d033adea91"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eca62bb0569de4d43a4dac06a2092a9d4ca1d702"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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