CVE-2026-74617
Received Received - Intake

NULL Pointer Dereference in Linux Kernel dibs Subsystem

Publication date: 2026-08-22

Last updated on: 2026-08-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: dibs: initialise dibs->lock in dibs_dev_alloc() dibs->lock is initialised by dibs_dev_add(), but a dibs device can already take interrupts before that call: ism_probe() runs ism_dev_init(), and hence request_irq(), before it calls dibs_dev_add(). No client can have registered a dmb at that point, so no dmb interrupt can occur, but a GID event interrupt can, and ism_handle_irq() takes dibs->lock unconditionally on entry, before it inspects anything else. Initialise the lock in dibs_dev_alloc() instead, so that it is valid as soon as a driver can publish the device to its interrupt handler.

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Meta Information

Published
2026-08-22
Last Modified
2026-08-22
Generated
2026-08-22
AI Q&A
2026-08-22
EPSS Evaluated
N/A
NVD
CVE-2026-74617
EUVD
EUVD-2026-64554

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 is a Linux kernel vulnerability where a lock in the dibs subsystem is not properly initialized before it can be accessed. The dibs->lock is supposed to be initialized by dibs_dev_add(), but a device can receive interrupts before this happens. Specifically, the ism_probe() function calls ism_dev_init() and request_irq() before dibs_dev_add(), which may lead to a GID event interrupt trying to access dibs->lock before it is initialized, causing undefined behavior.

Detection Guidance

This vulnerability is specific to the Linux kernel's dibs subsystem and involves a race condition where dibs->lock is accessed before initialization. Detection requires checking kernel logs for related errors or kernel crashes during device initialization or interrupt handling. Commands like dmesg or journalctl may show kernel oops or warnings related to dibs or ISM devices.

Impact Analysis

This vulnerability could lead to system instability or crashes if an interrupt handler attempts to use the uninitialized lock. It may cause kernel panics, data corruption, or denial of service if exploited by an attacker able to trigger the specific interrupt conditions.

Mitigation Strategies

Apply the latest kernel patch or update to a version where this issue is resolved. If patching is not immediately possible, avoid using ISM devices or disable the dibs subsystem if not required. Monitor kernel logs for signs of exploitation or crashes.

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