Bug 2468239 (CVE-2026-43451)

Summary: CVE-2026-43451 kernel: netfilter: nfnetlink_queue: fix entry leak in bridge verdict error path
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's netfilter component. A remote attacker can exploit this by sending specially crafted network packets that cause an error during VLAN attribute parsing in the nfnetlink_queue module. This leads to a memory leak, where kernel memory is not properly released. Repeated exploitation can exhaust kernel memory, resulting in a Denial of Service (DoS) for the system.
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Description OSIDB Bzimport 2026-05-08 15:06:28 UTC 
In the Linux kernel, the following vulnerability has been resolved:

netfilter: nfnetlink_queue: fix entry leak in bridge verdict error path

nfqnl_recv_verdict() calls find_dequeue_entry() to remove the queue
entry from the queue data structures, taking ownership of the entry.
For PF_BRIDGE packets, it then calls nfqa_parse_bridge() to parse VLAN
attributes.  If nfqa_parse_bridge() returns an error (e.g. NFQA_VLAN
present but NFQA_VLAN_TCI missing), the function returns immediately
without freeing the dequeued entry or its sk_buff.

This leaks the nf_queue_entry, its associated sk_buff, and all held
references (net_device refcounts, struct net refcount).  Repeated
triggering exhausts kernel memory.

Fix this by dropping the entry via nfqnl_reinject() with NF_DROP verdict
on the error path, consistent with other error handling in this file.
Comment 1 Keith Grant 2026-05-09 00:34:57 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050857-CVE-2026-43451-1195@gregkh/T