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VulnerabilityPublished Updated

CVE-2026-64423: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f91883031e5a62877a29ce139442973cbea769f1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f91883031e5a62877a29ce139442973cbea769f1, c6cb5f8ebe1c1a78710c19f102db9fe48b9e6ba9, 7993211bde166471dffac074dc965489f86531f8 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ e9897071350bd9d94a56b5b6f79c85b1a98fc7e7, < f91883031e5a62877a29ce139442973cbea769f1
Fixed in
  • f91883031e5a62877a29ce139442973cbea769f1
LinuxLinuxAffected
  • ≥ e9897071350bd9d94a56b5b6f79c85b1a98fc7e7, < c6cb5f8ebe1c1a78710c19f102db9fe48b9e6ba9
Fixed in
  • c6cb5f8ebe1c1a78710c19f102db9fe48b9e6ba9
LinuxLinuxAffected
  • ≥ e9897071350bd9d94a56b5b6f79c85b1a98fc7e7, < 7993211bde166471dffac074dc965489f86531f8
Fixed in
  • 7993211bde166471dffac074dc965489f86531f8
LinuxLinuxAffected
  • ≥ e9897071350bd9d94a56b5b6f79c85b1a98fc7e7, < 8820b530cb2388503d7418228d03ba074bf7a03e
Fixed in
  • 8820b530cb2388503d7418228d03ba074bf7a03e
LinuxLinuxAffected
  • ≥ e9897071350bd9d94a56b5b6f79c85b1a98fc7e7, < 412ba7def06ffe974ba9a1d862b022362c54ffa5
Fixed in
  • 412ba7def06ffe974ba9a1d862b022362c54ffa5
LinuxLinuxAffected
  • ≥ e9897071350bd9d94a56b5b6f79c85b1a98fc7e7, < 76d030ac95e17f91d69a595f17ebc5979700cf9a
Fixed in
  • 76d030ac95e17f91d69a595f17ebc5979700cf9a

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

References

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