CVE-2026-43374

In the Linux kernel, the following vulnerability has been resolved:

net: nexthop: fix percpu use-after-free in remove_nh_grp_entry

When removing a nexthop from a group, remove_nh_grp_entry() publishes

the new group via rcu_assign_pointer() then immediately frees the

removed entry's percpu stats with free_percpu(). However, the

synchronize_net() grace period in the caller remove_nexthop_from_groups()

runs after the free. RCU readers that entered before the publish still

see the old group and can dereference the freed stats via

nh_grp_entry_stats_inc() -> get_cpu_ptr(nhge->stats), causing a

use-after-free on percpu memory.

Fix by deferring the free_percpu() until after synchronize_net() in the

caller. Removed entries are chained via nh_list onto a local deferred

free list. After the grace period completes and all RCU readers have

finished, the percpu stats are safely freed.