CVE-2025-71226 in Linux
Summary
by MITRE • 02/18/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: Implement settime64 as stub for MVM/MLD PTP
Since commit dfb073d32cac ("ptp: Return -EINVAL on ptp_clock_register if required ops are NULL"), PTP clock registered through ptp_clock_register is required to have ptp_clock_info.settime64 set, however, neither MVM nor MLD's PTP clock implementation sets it, resulting in warnings when the interface starts up, like
WARNING: drivers/ptp/ptp_clock.c:325 at ptp_clock_register+0x2c8/0x6b8, CPU#1: wpa_supplicant/469 CPU: 1 UID: 0 PID: 469 Comm: wpa_supplicant Not tainted 6.18.0+ #101 PREEMPT(full) ra: ffff800002732cd4 iwl_mvm_ptp_init+0x114/0x188 [iwlmvm]
ERA: 9000000002fdc468 ptp_clock_register+0x2c8/0x6b8 iwlwifi 0000:01:00.0: Failed to register PHC clock (-22)
I don't find an appropriate firmware interface to implement settime64() for iwlwifi MLD/MVM, thus instead create a stub that returns -EOPTNOTSUPP only, suppressing the warning and allowing the PTP clock to be registered.
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Analysis
by VulDB Data Team • 07/28/2026
The vulnerability involves a critical inconsistency in the Linux kernel's Precision Time Protocol implementation within the iwlwifi driver for Intel wireless network adapters. This issue manifests as a missing required function pointer in the PTP clock registration process, specifically the settime64 operation that became mandatory following commit dfb073d32cac in the kernel's ptp subsystem. The problem affects both MVM (Multiple Virtual Machine) and MLD (Multi-Link Distribution) implementations of the iwlwifi driver, creating a fundamental mismatch between the kernel's expectations and the driver's actual capabilities.
The technical flaw stems from the kernel's requirement that all PTP clocks registered through ptp_clock_register must implement the settime64 function to properly handle time synchronization operations. However, the iwlwifi MVM and MLD drivers lack this implementation in their PTP clock infrastructure, causing the kernel to generate warnings during system initialization. The error message indicates that wpa_supplicant encounters a failure when attempting to register the PHC (Precision Hardware Clock) clock with error code -22, which corresponds to EINVAL or invalid argument. This occurs because the driver's ptp_clock_info structure does not contain a valid settime64 function pointer, violating the kernel's mandatory interface requirements.
The operational impact of this vulnerability extends beyond mere warning messages, as it prevents proper PTP clock registration and time synchronization capabilities for Intel wireless network adapters. When the PTP clock fails to register correctly, the wireless network hardware loses its ability to participate in precise time-stamping operations that are crucial for applications requiring high-precision timing, such as industrial automation, network monitoring, and real-time communication systems. The warning messages indicate that the iwl_mvm_ptp_init function cannot complete successfully, preventing proper initialization of the PTP subsystem for these wireless devices.
The mitigation strategy implemented addresses this issue by creating a stub implementation of settime64 that returns -EOPTNOTSUPP instead of allowing the registration to fail completely. This approach follows the principle of graceful degradation, where the system acknowledges the limitation while still allowing the PTP clock to be registered successfully. The solution maintains compatibility with existing kernel interfaces while preventing the propagation of error conditions that would otherwise disrupt wireless network operations. However, this represents a workaround rather than a complete solution, as it does not provide actual time-setting functionality for these wireless devices.
This vulnerability demonstrates several key security and reliability considerations within the Linux kernel's driver model and PTP implementation. The issue aligns with CWE-754 weakness category related to improper check for special error conditions, where the system fails to properly handle missing required operations in a security-critical subsystem. From an ATT&CK perspective, this vulnerability could potentially be leveraged by adversaries to disrupt time-sensitive network operations or create denial-of-service conditions in environments relying on precise timing synchronization. The fix demonstrates proper defensive programming techniques by implementing appropriate error handling and graceful degradation when hardware limitations prevent full feature implementation, while maintaining system stability through the use of standard error codes that indicate unsupported functionality rather than critical failures.