Bug 2516647 (CVE-2026-72229)

Summary: CVE-2026-72229 kernel: batman-adv: clean untagged VLAN on netdev registration failure
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: 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 `batman-adv` component of the Linux kernel. When a mesh interface is registered, an untagged VLAN object is created. If the network device (netdev) registration fails due to a veto, the cleanup process does not properly free this object. This can lead to a memory leak, potentially impacting system stability or performance over time.
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Description OSIDB Bzimport 2026-08-15 06:23:45 UTC 
In the Linux kernel, the following vulnerability has been resolved:

batman-adv: clean untagged VLAN on netdev registration failure

When an mesh interface is registered, it creates an untagged struct
batadv_meshif_vlan on top of it via the NETDEV_REGISTER notifier. But in
this process, another receiver of this notification can veto the
registration. The netdev registration will be aborted because of this veto.

The register_netdevice() call will try to clean up the net_device using
unregister_netdevice_queue() - which only uses the .priv_destructor to
free private resources. In this situation, .dellink will not be called.

The cleanup of the untagged batadv_meshif_vlan must thefore be done in the
destructor to avoid a leak of this object.
Comment 1 Keith Grant 2026-08-18 16:43:32 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081549-CVE-2026-72229-232f@gregkh/T