CVE-2026-64572

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ipv4: fib: free fib_alias with kfree_rcu() on insert error path<br /> <br /> fib_table_insert() publishes new_fa into the leaf&amp;#39;s fa_list with<br /> fib_insert_alias() before calling the fib entry notifiers. When a<br /> notifier fails, the error path removes new_fa with fib_remove_alias()<br /> (hlist_del_rcu) and frees it right away with kmem_cache_free().<br /> <br /> fib_table_lookup() walks that list under rcu_read_lock() only, so a<br /> concurrent lookup that already reached new_fa keeps reading it after the<br /> free:<br /> <br /> BUG: KASAN: slab-use-after-free in fib_table_lookup (net/ipv4/fib_trie.c:1601)<br /> Read of size 1 at addr ffff88810676d4eb by task exploit/297<br /> Call Trace:<br /> fib_table_lookup (net/ipv4/fib_trie.c:1601)<br /> ip_route_output_key_hash_rcu (net/ipv4/route.c:2814)<br /> ip_route_output_key_hash (net/ipv4/route.c:2705)<br /> __ip4_datagram_connect (net/ipv4/datagram.c:49)<br /> udp_connect (net/ipv4/udp.c:2144)<br /> __sys_connect (net/socket.c:2167)<br /> __x64_sys_connect (net/socket.c:2173)<br /> do_syscall_64<br /> entry_SYSCALL_64_after_hwframe<br /> which belongs to the cache ip_fib_alias of size 56<br /> <br /> Triggering the error path needs CAP_NET_ADMIN and a registered fib<br /> notifier that can reject a route; a netdevsim device whose IPv4 FIB<br /> resource is exhausted is enough.<br /> <br /> Free new_fa with alias_free_mem_rcu(), as fib_table_delete() already<br /> does for a fib_alias removed from the trie.