Riskcovery

CVE-2026-64423

ipv4: igmp: remove multicast group from hash table on device destruction

State
Published
Severity
7.8 High
Published
Jul 25, 2026
Updated
Oct 19, 2026
Reserved
Jul 19, 2026

Read the record on cve.org

Description

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->ip_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: <IRQ> 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 </IRQ>

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

Scores

CVSSScoreVectorSource
3.17.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux

Weaknesses

Affected Products

ProductVersions
LinuxLinux
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before 412ba7def06ffe974ba9a1d862b022362c54ffa5Affected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before c6cb5f8ebe1c1a78710c19f102db9fe48b9e6ba9Affected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before 5f42729d74bd6c61306d864423290d92962de4e1Affected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before 76d030ac95e17f91d69a595f17ebc5979700cf9aAffected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before 8820b530cb2388503d7418228d03ba074bf7a03eAffected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before 2ca18df1c2611f70eb3eb487e02ae85eb703b284Affected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before f91883031e5a62877a29ce139442973cbea769f1Affected
  • e9897071350bd9d94a56b5b6f79c85b1a98fc7e7 to before 7993211bde166471dffac074dc965489f86531f8Affected
LinuxLinux
  • 3.11Affected
  • before 3.11Not affected
  • 5.10.261 through 5.10.*Not affected
  • 5.15.212 through 5.15.*Not affected
  • 6.1.178 through 6.1.*Not affected
  • 6.6.145 through 6.6.*Not affected
  • 6.12.96 through 6.12.*Not affected
  • 6.18.39 through 6.18.*Not affected
  • 7.1.4 through 7.1.*Not affected
  • 7.2 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.