In the Linux kernel, the following vulnerability has been resolved:
ip6gre: Use cached t->net in ip6erspanchangelink().
After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of rtnllinkops"), ip6erspannewlink() correctly resolves the per-netns ip6gre hash via linknet. ip6erspanchangelink() was not converted in that series and still uses devnet(dev), which diverges from the device's creation netns after IFLANETNS_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, ip6greexitrtnlnet() walks the stale entry, producing a slab-use-after-free reported by KASAN, followed by a kernel BUG at net/core/dev.c (LISTPOISON1) in unregisternetdevicemany_notify().
Reachable from an unprivileged user namespace (unshare --user --map-root-user --net).
ip6grechangelink() earlier in the same file already uses the cached t->net; only ip6erspanchangelink() has the wrong shape.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46120.json",
"cna_assigner": "Linux"
}