{"id":"DEBIAN-CVE-2026-64423","details":"In the Linux kernel, the following vulnerability has been resolved:  ipv4: igmp: remove multicast group from hash table on device destruction  When a device is destroyed under RTNL, ip_mc_destroy_dev() iterates through the multicast list and calls ip_ma_put() on each membership, scheduling them for RCU reclamation. However, they are not unlinked from the device's multicast hash table (mc_hash).  Since the device remains published in dev-\u003eip_ptr until after ip_mc_destroy_dev() completes, concurrent RCU readers traversing mc_hash can still locate and access the multicast group after its refcount is decremented. If the RCU callback runs and frees the group while a reader is accessing it, a use-after-free occurs.  Fix this by unlinking the multicast group from mc_hash using ip_mc_hash_remove() before scheduling it for reclamation.  BUG: KASAN: slab-use-after-free in ip_check_mc_rcu+0x149/0x3f0 Read of size 4 at addr ffff888009bf1408 by task mausezahn/2276  Call Trace:  \u003cIRQ\u003e  dump_stack_lvl+0x67/0x90  print_report+0x175/0x7c0  kasan_report+0x147/0x180  ip_check_mc_rcu+0x149/0x3f0  udp_v4_early_demux+0x36d/0x12d0  ip_rcv_finish_core+0xb8b/0x1390  ip_rcv_finish+0x54/0x120  NF_HOOK+0x213/0x2b0  __netif_receive_skb+0x126/0x340  process_backlog+0x4f2/0xf00  __napi_poll+0x92/0x2c0  net_rx_action+0x583/0xc60  handle_softirqs+0x236/0x7f0  do_softirq+0x57/0x80  \u003c/IRQ\u003e  Allocated by task 2239:  kasan_save_track+0x3e/0x80  __kasan_kmalloc+0x72/0x90  ____ip_mc_inc_group+0x31a/0xa40  __ip_mc_join_group+0x334/0x3f0  do_ip_setsockopt+0x16fa/0x2010  ip_setsockopt+0x3f/0x90  do_sock_setsockopt+0x1ad/0x300  Freed by task 0:  kasan_save_track+0x3e/0x80  kasan_save_free_info+0x40/0x50  __kasan_slab_free+0x3a/0x60  __rcu_free_sheaf_prepare+0xd4/0x220  rcu_free_sheaf+0x36/0x190  rcu_core+0x8d9/0x12f0  handle_softirqs+0x236/0x7f0","modified":"2026-09-09T08:47:34.978398407Z","published":"2026-07-25T10:17:26.350Z","upstream":["CVE-2026-64423"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-64423"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.180-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.176-1","6.1.177-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not 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