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.
Affected products
linux: linux kernel
References9
- git.kernel.org/stable/c/01b71ff2857d3598337de11e7840a8e3ff21553c Patch
- git.kernel.org/stable/c/0fcf6731706f73494245a9c0d64f93bebf95bb51 Patch
- git.kernel.org/stable/c/1d324c2f43f70c965f25c58cc3611c779adbe47e Patch
- git.kernel.org/stable/c/311fdd26eb4443d43b909cc67a10f3a5fd1b21b2 Patch
- git.kernel.org/stable/c/7bd0f2b162b426b343a114e1b329f0d8d14fdc6e Patch
- git.kernel.org/stable/c/cf7fc624329e76c6394653d12353e1d033adea91 Patch
- git.kernel.org/stable/c/e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82 Patch
- git.kernel.org/stable/c/eca62bb0569de4d43a4dac06a2092a9d4ca1d702 Patch
- cert-portal.siemens.com/productcert/html/ssa-784472.html
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 3 · as of 15 November 2026
- CWE
- CWE-416
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