CVE-2025-38121 in Linux
Summary
by MITRE • 07/03/2025
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mld: avoid panic on init failure
In case of an error during init, in_hw_restart will be set, but it will never get cleared. Instead, we will retry to init again, and then we will act like we are in a restart when we are actually not.
This causes (among others) to a NULL pointer dereference when canceling rx_omi::finished_work, that was not even initialized, because we thought that we are in hw_restart.
Set in_hw_restart to true only if the fw is running, then we know that FW was loaded successfully and we are not going to the retry loop.
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Analysis
by VulDB Data Team • 04/18/2026
The vulnerability CVE-2025-38121 affects the Linux kernel's iwlwifi wireless driver implementation, specifically within the Multi-Link Device (MLD) functionality. This issue stems from improper handling of hardware initialization states during wireless network adapter setup processes. The flaw manifests when the driver encounters errors during the initialization phase of Intel wireless hardware components, creating a dangerous state transition that leads to system instability. The root cause lies in the driver's failure to properly manage the in_hw_restart flag, which serves as a critical state indicator for hardware restart operations within the wireless subsystem.
The technical implementation flaw occurs when the iwlwifi driver attempts to initialize wireless hardware components and encounters initialization failures. During these error conditions, the in_hw_restart flag gets incorrectly set to true but never gets cleared, creating a persistent false positive state. This mismanagement causes the driver to incorrectly assume it's operating within a hardware restart scenario even when it's actually in a fresh initialization state. The vulnerability is particularly dangerous because it operates at the kernel level where improper state management can lead to complete system crashes and potential denial of service conditions. This specific issue is classified under CWE-394, representing an insufficient control flow management problem in kernel space operations.
The operational impact of this vulnerability extends beyond simple system instability to potentially catastrophic failure modes within wireless networking infrastructure. When the driver incorrectly assumes it's in a hardware restart state, it attempts to cancel work items that were never properly initialized, leading to NULL pointer dereference exceptions. This particular failure mode can cause kernel panics and system crashes, effectively rendering wireless networking capabilities unusable until system reboot occurs. The vulnerability affects systems running Linux kernels with iwlwifi drivers, particularly those supporting Intel wireless hardware with MLD capabilities, making it a significant concern for enterprise and consumer devices relying on wireless connectivity.
Mitigation strategies for CVE-2025-38121 focus on implementing proper state management within the wireless driver initialization sequence. The recommended approach involves modifying the driver logic to only set in_hw_restart to true when the firmware is actually running and has been successfully loaded, rather than during error conditions that trigger retry loops. This prevents the erroneous state propagation that leads to NULL pointer dereferences. System administrators should prioritize kernel updates that include the patched iwlwifi driver implementation, which addresses the improper flag management through careful initialization state checking. Organizations should also implement monitoring for wireless subsystem stability and consider temporary disabling of wireless functionality during patch deployment to prevent potential service interruptions. This vulnerability aligns with ATT&CK technique T1499.004, representing a denial of service through kernel-level resource manipulation, and demonstrates the critical importance of proper state machine implementation in kernel drivers.