CVE-2026-97972
Received Received - Intake

Linux kernel MACB MDIO node reference leak fix

Publication date: 2026-09-25

Last updated on: 2026-09-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net: macb: put the "mdio" child node reference on success macb_mii_init() holds the reference returned by of_get_child_by_name() for macb_mdiobus_register() and drops it only on the error paths, so every successful probe leaks a node reference. On a CM5, overlay removal after four bind cycles reports OF: ERROR: memory leak, expected refcount 1 instead of 5 Drop the reference after registration, where __mdiobus_register() has already taken its own for the lifetime of the bus.

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Meta Information

Published
2026-09-25
Last Modified
2026-09-25
Generated
2026-09-25
AI Q&A
2026-09-25
EPSS Evaluated
N/A
NVD
CVE-2026-97972
EUVD
EUVD-2026-86826

Affected Vendors & Products

Currently, no data is known.

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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 is a memory leak in the Linux kernel's macb network driver. The issue occurs in the macb_mii_init() function where a reference to a device tree node is not properly released after successful initialization. The function acquires a reference using of_get_child_by_name() but only releases it in error paths, causing a leak on successful probe. This leads to an increasing reference count with each driver bind cycle, eventually causing an error during overlay removal due to unexpected reference counts.

Detection Guidance

This vulnerability is specific to the Linux kernel's macb network driver and involves a memory leak in the MDIO child node reference. Detection requires checking kernel logs for memory leak warnings or overlay removal errors, particularly after multiple bind cycles on a CM5 system.

Impact Analysis

This vulnerability primarily affects systems using the macb network driver, particularly on CM5 platforms. The main impact is a memory leak that accumulates with each driver initialization cycle. Over time, this could lead to system instability, reduced performance, or eventual failure due to exhausted system resources. It may also cause errors during device tree overlay removal operations.

Mitigation Strategies

Apply the latest Linux kernel patches that resolve this issue. Monitor kernel logs for OF: ERROR messages indicating memory leaks. Reboot the system if overlay removal errors are detected to clear leaked references.

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