{"cve":"CVE-2026-64423","nvd":{"published":"2026-07-25T10:17:26.350","modified":"2026-10-19T21:17:37.280","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: igmp: remove multicast group from hash table on device destruction\n\nWhen a device is destroyed under RTNL, ip_mc_destroy_dev() iterates through\nthe multicast list and calls ip_ma_put() on each membership, scheduling\nthem for RCU reclamation. However, they are not unlinked from the device's\nmulticast hash table (mc_hash).\n\nSince the device remains published in dev->ip_ptr until after\nip_mc_destroy_dev() completes, concurrent RCU readers traversing mc_hash\ncan still locate and access the multicast group after its refcount is\ndecremented. If the RCU callback runs and frees the group while a reader is\naccessing it, a use-after-free occurs.\n\nFix this by unlinking the multicast group from mc_hash using\nip_mc_hash_remove() before scheduling it for reclamation.\n\nBUG: KASAN: slab-use-after-free in ip_check_mc_rcu+0x149/0x3f0\nRead of size 4 at addr ffff888009bf1408 by task mausezahn/2276\n\nCall Trace:\n <IRQ>\n dump_stack_lvl+0x67/0x90\n print_report+0x175/0x7c0\n kasan_report+0x147/0x180\n ip_check_mc_rcu+0x149/0x3f0\n udp_v4_early_demux+0x36d/0x12d0\n ip_rcv_finish_core+0xb8b/0x1390\n ip_rcv_finish+0x54/0x120\n NF_HOOK+0x213/0x2b0\n __netif_receive_skb+0x126/0x340\n process_backlog+0x4f2/0xf00\n __napi_poll+0x92/0x2c0\n net_rx_action+0x583/0xc60\n handle_softirqs+0x236/0x7f0\n do_softirq+0x57/0x80\n </IRQ>\n\nAllocated by task 2239:\n kasan_save_track+0x3e/0x80\n __kasan_kmalloc+0x72/0x90\n ____ip_mc_inc_group+0x31a/0xa40\n __ip_mc_join_group+0x334/0x3f0\n do_ip_setsockopt+0x16fa/0x2010\n ip_setsockopt+0x3f/0x90\n do_sock_setsockopt+0x1ad/0x300\n\nFreed by task 0:\n kasan_save_track+0x3e/0x80\n kasan_save_free_info+0x40/0x50\n __kasan_slab_free+0x3a/0x60\n __rcu_free_sheaf_prepare+0xd4/0x220\n rcu_free_sheaf+0x36/0x190\n rcu_core+0x8d9/0x12f0\n handle_softirqs+0x236/0x7f0","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/2ca18df1c2611f70eb3eb487e02ae85eb703b284","https://git.kernel.org/stable/c/412ba7def06ffe974ba9a1d862b022362c54ffa5","https://git.kernel.org/stable/c/5f42729d74bd6c61306d864423290d92962de4e1","https://git.kernel.org/stable/c/76d030ac95e17f91d69a595f17ebc5979700cf9a","https://git.kernel.org/stable/c/7993211bde166471dffac074dc965489f86531f8"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:56:58.798400159+00:00"},"epss":{"cve":"CVE-2026-64423","score":0.00132,"percentile":0.02725,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}