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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HWeakness enumeration
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= 2d665034f239412927b1e71329f20f001c92da09, < 7bd0f2b162b426b343a114e1b329f0d8d14fdc6e; >= 2d665034f239412927b1e71329f20f001c92da09, < 01b71ff2857d3598337de11e7840a8e3ff21553c; >= 2d665034f239412927b1e71329f20f001c92da09, < 0fcf6731706f73494245a9c0d64f93bebf95bb51; >= 2d665034f239412927b1e71329f20f001c92da09, < eca62bb0569de4d43a4dac06a2092a9d4ca1d702; >= 2d665034f239412927b1e71329f20f001c92da09, < 311fdd26eb4443d43b909cc67a10f3a5fd1b21b2; >= 2d665034f239412927b1e71329f20f001c92da09, < e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82; >= 2d665034f239412927b1e71329f20f001c92da09, < cf7fc624329e76c6394653d12353e1d033adea91; >= 2d665034f239412927b1e71329f20f001c92da09, < 1d324c2f43f70c965f25c58cc3611c779adbe47e; c6d72628352c949629af619b77b042e0fb5245e7; >= 4.16.12, < 4.17 |
| Linux | Linux | 4.17 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | < * |
References
- https://git.kernel.org/stable/c/01b71ff2857d3598337de11e7840a8e3ff21553cPatch
- https://git.kernel.org/stable/c/0fcf6731706f73494245a9c0d64f93bebf95bb51Patch
- https://git.kernel.org/stable/c/1d324c2f43f70c965f25c58cc3611c779adbe47ePatch
- https://git.kernel.org/stable/c/311fdd26eb4443d43b909cc67a10f3a5fd1b21b2Patch
- https://git.kernel.org/stable/c/7bd0f2b162b426b343a114e1b329f0d8d14fdc6ePatch
- https://git.kernel.org/stable/c/cf7fc624329e76c6394653d12353e1d033adea91Patch
- https://git.kernel.org/stable/c/e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82Patch
- https://git.kernel.org/stable/c/eca62bb0569de4d43a4dac06a2092a9d4ca1d702Patch
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
Timeline
- Published
- May 28, 2026
- Last modified
- Oct 19, 2026
- NVD status
- Undergoing Analysis