CVE-2026-63834
Received Received - Intake

batman-adv tp_meter Memory Exhaustion via Unbounded List

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: batman-adv: tp_meter: restrict number of unacked list entries When the unacked_list is unbound, an attacker could send messages with small lengths and appropriated seqno + gaps to force the receiver to allocate more and more unacked_list entries. And the end either causing an out-of-memory situation or increase the management overhead for the (large) list that significant portions of CPU cycles are wasted in searching through the list. When limiting the list to a specific number, it is important to still correctly add a new entry to the list. But if the list became larger than the limit, the last entry of the list (with the highest seqno) must be dropped to still allow the earlier seqnos to finish and therefore to continue the process. Otherwise, the process might get stuck with too high seqnos which are not handled by batadv_tp_ack_unordered().

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-63834
EUVD
EUVD-2026-45500

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
batman-adv batman-adv *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel's batman-adv module allows an attacker to send crafted messages that force the receiver to allocate excessive entries in an internal list called unacked_list. This can lead to out-of-memory situations or waste CPU cycles searching through a large list.

Detection Guidance

This vulnerability is specific to the batman-adv kernel module and involves unbounded memory allocation in the tp_meter component. Detection requires checking for unusual memory usage patterns or CPU load spikes in systems running batman-adv. Monitor for processes consuming excessive memory or CPU, particularly in batadv_tp_meter or related functions. Check kernel logs for out-of-memory errors or high seqno gaps in tp_meter operations.

Impact Analysis

An attacker could exploit this to cause denial-of-service by consuming system memory or degrading performance due to high CPU usage from managing an oversized list.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a resource exhaustion issue in the Linux kernel's batman-adv module that could lead to denial-of-service conditions by consuming excessive memory or CPU resources.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the batman-adv tp_meter unacked_list vulnerability. Monitor system memory usage and CPU load for unusual spikes that may indicate exploitation attempts.

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