CVE-2026-74519 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: devicetree: don't free uninitialized dev_name on error path
dt_remember_or_free_map() duplicates dev_name for each map entry. If kstrdup_const() fails, dt_free_map() frees dev_name in all num_maps entries, including entries that have not been initialized.
Some pinctrl drivers, including pinctrl-imx, allocate the map with kmalloc() and leave dev_name for the core to initialize. The untouched entries therefore contain uninitialized data which is passed to kfree_const().
Reproduced on qemu's mcimx6ul-evk (pinctrl-imx) with failslab injection while binding the pinctrl-consuming device, under KASAN:
BUG: KASAN: double-free in dt_free_map+0x34/0xa4 Free of addr c425a900 by task init/1 kfree from dt_free_map+0x34/0xa4 dt_free_map from dt_remember_or_free_map+0x184/0x198 dt_remember_or_free_map from pinctrl_dt_to_map+0x33c/0x4c8 pinctrl_dt_to_map from create_pinctrl+0x9c/0x5c0
Initialize all dev_name fields to NULL before duplicating the device name, making the full-map cleanup safe after a partial failure.
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Analysis
by VulDB Data Team • 08/15/2026
This vulnerability resides in the Linux kernel's pinctrl subsystem within the device tree processing functionality. The issue manifests in the dt_remember_or_free_map() function which handles memory allocation and management for pin configuration maps. When kstrdup_const() fails during the duplication process, the error handling path attempts to free dev_name fields across all map entries regardless of their initialization state. This creates a dangerous condition where uninitialized memory locations are passed to kfree_const(), leading to potential double-free conditions and system instability.
The technical flaw stems from improper memory management practices in the error recovery path of device tree pin configuration processing. Specifically, when memory allocation fails partway through map entry processing, the cleanup function dt_free_map() iterates through all num_maps entries without checking whether each entry was successfully initialized. This violates fundamental safe programming practices and creates a condition where freed memory locations may be accessed multiple times. The vulnerability particularly affects pinctrl drivers like pinctrl-imx that use kmalloc() for map allocation and rely on the core to initialize dev_name fields, leaving some entries with uninitialized data that gets incorrectly processed during error cleanup.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially compromise system stability and security. When triggered through KASAN testing with failslab injection on qemu's mcimx6ul-evk platform, the double-free condition can cause kernel panics or undefined behavior that may be exploited by malicious actors. The vulnerability demonstrates a classic improper error handling pattern that can lead to denial of service conditions or potentially more severe security implications in embedded systems where pinctrl functionality is critical for hardware initialization and device operation. This type of memory safety issue is particularly concerning in kernel space where errors can lead to complete system compromise.
The fix involves initializing all dev_name fields to NULL before attempting device name duplication, ensuring that any partial failure during map creation leaves entries in a safe state for cleanup operations. This approach follows the principle of defensive programming and aligns with CWE-459 which addresses incomplete cleanup issues in software systems. The solution prevents the erroneous freeing of uninitialized memory while maintaining the integrity of the pinctrl subsystem's device tree processing capabilities. From an ATT&CK perspective, this vulnerability relates to privilege escalation and denial of service techniques that could be leveraged by adversaries to disrupt system operations or gain unauthorized access to embedded devices running vulnerable kernel versions.
This vulnerability represents a critical safety issue in Linux kernel memory management that highlights the importance of proper error handling in kernel subsystems. The fix ensures that cleanup operations remain safe even when partial failures occur, preventing potential exploitation through memory corruption attacks. System administrators should prioritize updating affected kernel versions to mitigate this risk, particularly on embedded platforms where pinctrl functionality is essential for hardware initialization and device operation.