Bug 2492118 (CVE-2026-52931)

Summary: CVE-2026-52931 kernel: batman-adv: tp_meter: avoid use of uninit sender vars
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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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 `batman-adv` `tp_meter` module of the Linux kernel. A remote attacker could exploit this vulnerability by sending a specially crafted acknowledgment (ACK) packet to a node configured as a receiver in an ongoing `tp_meter` session. This could lead to the use of uninitialized sender variables, resulting in undefined behavior and potentially a denial of service.
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Description OSIDB Bzimport 2026-06-24 08:02:51 UTC 
In the Linux kernel, the following vulnerability has been resolved:

batman-adv: tp_meter: avoid use of uninit sender vars

batadv_tp_recv_ack() and batadv_tp_stop() are only valid for tp_vars in the
BATADV_TP_SENDER role. When called with a BATADV_TP_RECEIVER role, it
proceeds to read sender-only members that were never initialized, leading
to undefined behavior.

This can be triggered when a node that is currently acting as a receiver in
an ongoing tp_meter session receives a malicious ACK packet.

Guard against this by checking tp_vars->role immediately after the
lookup and bailing out if it is not BATADV_TP_SENDER, before any of
those members are accessed.
Comment 1 Mauro Matteo Cascella 2026-06-24 14:35:49 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062432-CVE-2026-52931-f85c@gregkh/T