CVE-2026-43084: netfilter: nfnetlink_queue: make hash table per queue

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-06 · updated 2026-10-19
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_queue: make hash table per queue Sharing a global hash table among all queues is tempting, but it can cause crash: BUG: KASAN: slab-use-after-free in nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue] [..] nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue] nfnetlink_rcv_msg+0x46a/0x930 kmem_cache_alloc_node_noprof+0x11e/0x450 struct nf_queue_entry is freed via kfree, but parallel cpu can still encounter such an nf_queue_entry when walking the list. Alternative fix is to free the nf_queue_entry via kfree_rcu() instead, but as we have to alloc/free for each skb this will cause more mem pressure.

Affected products

Linux kernel: from 6.12.75 before 6.12.83; from 6.18.14 before 6.18.24; from 6.19.4 before 6.19.14 — fixed in 6.12.83, 6.18.24, 6.19.14

How to fix

Upgrade to a fixed version: Linux kernel 6.12.83, 6.18.24, 6.19.14. Check the vendor advisory for mitigations.

References

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