Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 5.10.0 (+9 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Amazon Linux 2023 | Released |
57 kernels
|
| Debian 11 | Planned | — |
| Debian 11 cloud | Planned | — |
| Debian 12 | Planned | — |
| Debian 13 | Released |
7 kernels
|
| Proxmox VE 7 5.15 | Released |
47 kernels
|
| RHEL 8 | In Progress | — |
| RHEL 9 | In Progress | — |
| Ubuntu 20.04 HWE AWS | Released |
57 kernels
|
| Ubuntu 20.04 HWE Azure | Released |
40 kernels
|
| Ubuntu 22.04 | Released |
97 kernels
|
| Ubuntu 22.04 AWS | Released |
88 kernels
|
| Ubuntu 22.04 Azure | Released |
78 kernels
|
| Ubuntu 24.04 | Planned | — |