CVE-2025-71226: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-71226 is a rejected/withdrawn CVE related to a missing settime64 implementation in the Linux kernel's iwlwifi driver (MVM/MLD PTP clock subsystem). The issue was originally identified as causing PTP clock registration failures with warnings during interface startup, following commit dfb073d32cac which made ptp_clock_info.settime64 a required operation. The CVE was assigned an estimated CVSS v3.1 score of 5.5 (Medium) before being rejected by its CVE Numbering Authority (Red Hat CVE, Red Hat Bugzilla).

The root cause is a missing implementation of the ptp_clock_info.settime64 callback in the Linux kernel's iwlwifi MVM and MLD PTP clock drivers (CWE-476 / missing implementation). After commit dfb073d32cac ("ptp: Return -EINVAL on ptp_clock_register if required ops are NULL") changed PTP clock registration requirements, the absence of settime64 caused ptp_clock_register() to fail with -EINVAL (-22), generating a kernel WARNING in drivers/ptp/ptp_clock.c:325 during interface startup (e.g., triggered by wpa_supplicant). The fix introduces a stub implementation returning -EOPTNOTSUPP, suppressing the warning and allowing successful PTP clock registration (Red Hat Bugzilla).

When an affected iwlwifi interface starts up, a kernel WARNING is generated and the PTP clock fails to register, resulting in the log message iwlwifi 0000:01:00.0: Failed to register PHC clock (-22). This prevents normal operation of precision time synchronization (PTP/PHC) features on systems using Intel WiFi hardware with the iwlwifi driver. The impact is limited to availability of the PTP clock subsystem — there is no confidentiality or integrity impact — and it does not affect general WiFi connectivity (Red Hat Bugzilla, Red Hat CVE).

A patch is available that implements settime64 as a stub returning -EOPTNOTSUPP in the iwlwifi MVM/MLD PTP driver, suppressing the warning and restoring PTP clock registration. Systems that do not require PTP clock functionality can disable the iwlwifi PTP feature as a temporary workaround until the kernel patch is applied. Review and test kernel updates in your environment before deployment to ensure compatibility with your Linux kernel version and Intel WiFi hardware (Red Hat Bugzilla).

This CVE received minimal industry attention and was subsequently rejected by its CVE Numbering Authority, indicating it did not meet the threshold for a security vulnerability. Red Hat tracked it via Bugzilla and the upstream fix was referenced via the Linux CVE announcement mailing list (Red Hat Bugzilla).