Vulnerabilidad · Publicado 25/09/2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: fix fib6 walker UAF on seq stop
ipv6_route_iter_active() treats a walker in FWS_U at the table root as
already unlinked. fib6_del_route() can move a still-linked walker into
that same state when the current leaf is the last route at the root,
so ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq
private objec…
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix fib6 walker UAF on seq stop ipv6_route_iter_active() treats a walker in FWS_U at the table root as already unlinked. fib6_del_route() can move a still-linked walker into that same state when the current leaf is the last route at the root, so ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq private object can then be freed while it remains on net->ipv6.fib6_walkers. A later route deletion walks the dangling list and uses the freed walker. Use the list head as membership state and reinitialize it when unlinking. Keep the existing w->node check so a never-started iterator with a zeroed private object is not treated as linked. The same stop helper is used by /proc/net/ipv6_route and by the BPF ipv6_route iterator. The BPF show path only widens the race.
Score: 7.8/10 — Severidad: HIGH — Estado NIST: Received
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Publicado en NIST NVD.