Bug 2516408 (CVE-2026-72246)

Summary: CVE-2026-72246 kernel: netfilter: flowtable: use correct direction to set up tunnel route
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
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 Linux kernel's netfilter flowtable component. This vulnerability arises from an error in how the system sets up tunnel routes, specifically in handling network packet encapsulation and tunnel information. An attacker could potentially exploit this to cause incorrect network traffic routing or unexpected packet behavior. This could lead to network disruptions or a denial of service (DoS).
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Description OSIDB Bzimport 2026-08-15 06:10:53 UTC 
In the Linux kernel, the following vulnerability has been resolved:

netfilter: flowtable: use correct direction to set up tunnel route

The layer 2 encapsulation and layer 3 tunnel information in the xmit
path is taken from the other tuple, because the tunnel information that
is included in the tuple for hashtable lookups is also used to perform
the egress encapsulation in the transmit path.

This patch uses the correct direction when setting up the tunnel, the
original proposed patch to address this fix uses the reversed direction.

While at it, remove the redundant check to call dst_release() to drop
the reference on the dst that was obtained from the forward path, which
is not useful in the direct xmit path unless tunneling is performed.
Comment 1 Keith Grant 2026-08-18 17:14:55 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081552-CVE-2026-72246-63e0@gregkh/T