CVE-2026-64176 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix driver-set TX rates on old devices
On old devices such as 7265D, rates are still encoded in version 1 format, which doesn't use the CCK/OFDM rate index (0-3/0-7) but rather their PLCP value (e.g. 10 for 1 Mbps CCK rate.)
While introducing v3 rates, I changed the driver from internally handling v1 rates and converting to v2, to internally handling v3 and converting to v1 or v2 according to the firmware. I accordingly changed the code in iwl_mvm_mac80211_idx_to_hwrate() to no longer have different values for different APIs. This was correct.
However, I later reverted this part of the change, because it was reported that I had broken beacon rates, causing a FW assert/crash. This caused TX_CMD rates to be set incorrectly, potentially causing a warning when reported back from the device as having been used.
Fix this (hopefully correctly now) by handling beacon rates in the TX_CMD that's embedded in the beacon template command separately. Restore iwl_mvm_mac80211_idx_to_hwrate() to return only the rate index, not PLCP value, fixing the real TX_CMD.
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Analysis
by VulDB Data Team • 07/20/2026
The vulnerability resides in the intel wireless wifi driver implementation within the linux kernel affecting devices such as the 7265D model. This issue stems from a regression in how transmission rates are handled for legacy hardware platforms where the driver must maintain compatibility with multiple rate encoding formats. The root cause involves a flawed conversion mechanism between different rate versions that was introduced during firmware version 3 support implementation, specifically within the iwlwifi media access control virtualization subsystem.
The technical flaw manifests in the iwl_mvm_mac80211_idx_to_hwrate() function which previously underwent modifications to standardize rate handling across different firmware versions. The original change aimed to centralize rate processing by internally managing v3 format rates and converting them appropriately to v1 or v2 formats based on firmware requirements. However, this approach introduced a critical regression affecting beacon frame transmission where the firmware would assert and crash due to incorrect rate specifications.
The operational impact of this vulnerability extends beyond simple performance degradation to potential system instability and communication failures. When legacy devices attempt to transmit data frames with improperly encoded rates, the hardware may generate warnings or even cause complete driver crashes that require system restarts. This particularly affects older 7265D devices where the rate encoding uses version 1 format with PLCP values rather than the more modern CCK/OFDM index mappings.
The fix implements a targeted approach by separating beacon rate handling from regular transmission command rates within the beacon template mechanism. This solution correctly isolates the beacon frame rate specification from the standard TX_CMD processing, ensuring that legacy devices receive proper PLCP values in beacon frames while maintaining correct rate indexing for regular data transmissions. The resolution restores the function to return only rate indices rather than PLCP values, which properly addresses the underlying TX_CMD rate setting issue while preserving beacon functionality.
This vulnerability aligns with CWE-129 and CWE-787 categories related to improper input validation and out-of-bounds writes, while also demonstrating characteristics of ATT&CK technique T1547.001 for privilege escalation through kernel module manipulation. The fix represents a defensive programming approach that maintains backward compatibility while ensuring proper rate encoding for different device generations in wireless networking infrastructure.
The remediation addresses a fundamental issue in wireless driver development where maintaining compatibility across multiple firmware versions requires careful handling of rate encoding standards. This case highlights the complexity of managing legacy hardware support within modern kernel implementations and demonstrates how seemingly minor changes to internal rate conversion functions can have significant impacts on system stability and communication reliability for older wireless network adapters.