{"id":"AZL-94473","summary":"CVE-2026-64572 affecting package kernel for versions less than 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: fib: free fib_alias with kfree_rcu() on insert error path\n\nfib_table_insert() publishes new_fa into the leaf's fa_list with\nfib_insert_alias() before calling the fib entry notifiers. When a\nnotifier fails, the error path removes new_fa with fib_remove_alias()\n(hlist_del_rcu) and frees it right away with kmem_cache_free().\n\nfib_table_lookup() walks that list under rcu_read_lock() only, so a\nconcurrent lookup that already reached new_fa keeps reading it after the\nfree:\n\n BUG: KASAN: slab-use-after-free in fib_table_lookup (net/ipv4/fib_trie.c:1601)\n Read of size 1 at addr ffff88810676d4eb by task exploit/297\n Call Trace:\n  fib_table_lookup (net/ipv4/fib_trie.c:1601)\n  ip_route_output_key_hash_rcu (net/ipv4/route.c:2814)\n  ip_route_output_key_hash (net/ipv4/route.c:2705)\n  __ip4_datagram_connect (net/ipv4/datagram.c:49)\n  udp_connect (net/ipv4/udp.c:2144)\n  __sys_connect (net/socket.c:2167)\n  __x64_sys_connect (net/socket.c:2173)\n  do_syscall_64\n  entry_SYSCALL_64_after_hwframe\n which belongs to the cache ip_fib_alias of size 56\n\nTriggering the error path needs CAP_NET_ADMIN and a registered fib\nnotifier that can reject a route; a netdevsim device whose IPv4 FIB\nresource is exhausted is enough.\n\nFree new_fa with alias_free_mem_rcu(), as fib_table_delete() already\ndoes for a fib_alias removed from the trie.","modified":"2026-08-28T17:48:06.806782396Z","published":"2026-08-05T08:16:36Z","upstream":["CVE-2026-64572"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64572"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-94473.json"}}],"schema_version":"1.9.0"}