Bug 2524483 (CVE-2026-74746)

Summary: CVE-2026-74746 kernel: netfilter: flowtable: publish GC-visible tuple last
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the netfilter flowtable component of the Linux kernel. This vulnerability occurs due to a timing issue where the system's garbage collection can free a network flow while it is still being set up. This can lead to a 'use-after-free' condition, where the system attempts to access memory that has already been released. This memory corruption could potentially result in a system crash (denial of service) or, in certain circumstances, allow for arbitrary code execution.
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Description OSIDB Bzimport 2026-08-26 14:59:34 UTC 
In the Linux kernel, the following vulnerability has been resolved:

netfilter: flowtable: publish GC-visible tuple last

nf_flow_table_iterate() only treats original-direction tuple nodes as
owning entries. Publishing the original node first lets GC observe and
free a flow while flow_offload_add() is still inserting the reply node.
Publish the reply node first and the original node last so GC never
sees a partially installed flow.

KASAN can trigger slab-use-after-free read and write reports in the
flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,
flow_offload_lookup, etc.).
Comment 1 gkamathe 2026-08-27 11:41:45 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082658-CVE-2026-74746-c2f9@gregkh/T