CVE-2026-63835
Received Received - Intake

batman-adv OGM Aggregation Use-After-Free

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: v: prevent OGM aggregation on disabled hardif When an interface gets disabled, the worker is correctly disabled by batadv_hardif_disable_interface() -> ... -> batadv_v_ogm_iface_disable(). In this process, the skb aggr_list is also freed. But batadv_v_ogm_send_meshif() can still queue new skbs (via batadv_v_ogm_queue_on_if()) to the aggr_list. This will only stop after all cores can no longer find the RCU protected list of hard interfaces. These queued skbs will never be freed or consumed by batadv_v_ogm_aggr_work. The batadv_v_ogm_iface_disable() function must block batadv_v_ogm_queue_on_if() to avoid leak of skbs.

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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-2026-63835
EUVD
EUVD-2026-45501

Affected Vendors & Products

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

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a memory leak in the batman-adv protocol. When a network interface is disabled, the system fails to properly block new data packet processing. This causes queued packets to remain in memory indefinitely, as they are never freed or processed by the aggregation worker.

Detection Guidance

This vulnerability involves memory leaks in the batman-adv kernel module when interfaces are disabled. Detection requires checking for kernel logs related to batman-adv and monitoring memory usage. Look for messages about skb leaks or interface disable failures. Use commands like dmesg | grep batman-adv or journalctl -k | grep batman-adv to inspect logs. Check memory consumption with commands like free -m or top to identify unusual skb-related memory growth.

Impact Analysis

The vulnerability could lead to system resource exhaustion due to unreleased memory from queued packets. This may cause performance degradation, crashes, or instability in systems running affected Linux kernel versions with batman-adv enabled.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA as it pertains to a memory leak in the Linux kernel's batman-adv module, which is unrelated to data protection or privacy controls required by these regulations.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for CVE-2026-63835. Monitor network interfaces for unexpected skb leaks or crashes in batman-adv components.

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