CVE-2026-99189
Received Received - Intake

Race Condition in Linux Kernel GPIO MXC Driver

Publication date: 2026-10-28

Last updated on: 2026-10-28

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: gpio: mxc: fix race between chained IRQ handler install and probe completion mxc_update_irq_chained_handler() is called before the IRQ domain, the generic IRQ chip, and the port list entry are set up. If an interrupt arrives in that window: - mx3_gpio_irq_handler() calls generic_handle_domain_irq() with port->domain still NULL. - mx2_gpio_irq_handler() walks mxc_gpio_ports, but the port has not been added to the list yet. Additionally, if any of the subsequent probe steps (gpio_generic_chip_init(), devm_gpiochip_add_data(), irq_domain_create_legacy(), or mxc_gpio_init_gc()) fail, the error paths never unregister the chained handler, leaving a dangling handler that points at freed memory. Move the handler installation after all its dependencies are ready and after list_add_tail(), so the handler is never live while the data structures it touches are incomplete, and is never installed if probe fails.

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Meta Information

Published
2026-10-28
Last Modified
2026-10-28
Generated
2026-10-28
AI Q&A
2026-10-28
EPSS Evaluated
N/A
NVD
CVE-2026-99189
EUVD
EUVD-2026-111941

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
Linux Linux 5f6d1998adeb5374ef248b5ba2e2a0c30ab0f60b
Linux Linux 5f6d1998adeb5374ef248b5ba2e2a0c30ab0f60b
Linux Linux 5f6d1998adeb5374ef248b5ba2e2a0c30ab0f60b
Linux Linux 6.6

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Exploitability

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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 race condition in the GPIO (General Purpose Input/Output) driver for MXC (i.MX Crossbar) devices. The issue occurs when the interrupt handler is installed before the necessary data structures are fully initialized. If an interrupt arrives during this window, it can cause a crash or undefined behavior because the handler tries to access incomplete or uninitialized data.

Detection Guidance

This vulnerability is specific to the Linux kernel's GPIO subsystem and cannot be detected via network scans or typical system commands. It requires kernel code inspection or runtime monitoring for race conditions during GPIO probe operations. Check kernel logs for GPIO-related errors or crashes during system boot or device probe events.

Impact Analysis

This vulnerability could lead to system instability, crashes, or potential security issues if exploited. Systems using affected Linux kernel versions with MXC GPIO devices may experience unexpected behavior or failures during interrupt handling, potentially disrupting normal operations.

Mitigation Strategies

Apply the latest kernel patches from your Linux distribution to ensure the fix for CVE-2026-99189 is included. If patching is not immediately possible, avoid using affected GPIO devices until the update is applied. Monitor system logs for GPIO-related errors as a potential indicator of exploitation.

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