CVE-2026-64506 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw89: correct drop logic for malformed AMPDU frames
The previous commit aims to fix issue caused by malformed AMPDU frames. But the drop logic fails to deal with the first AMPDU packet paired with certain range of sequence number, and leads to unexpected packet drop. It is more likely to encounter this failure when there are busy traffic during rekey process and could lead to disconnection from the AP. Fix this by adding a initial state judgement and only reset status during pairwise rekey.
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Analysis
by VulDB Data Team • 07/26/2026
The vulnerability resides in the rtw89 wireless driver component of the Linux kernel, specifically addressing improper handling of malformed AMPDU frames within the wifi subsystem. This issue represents a critical flaw in the wireless communication stack that can lead to service disruption and connectivity failures. The problem manifests when the driver encounters malformed aggregated mac protocol data unit frames during normal network operations, particularly under conditions of high traffic load.
The technical root cause involves flawed packet drop logic within the wireless driver's frame processing pipeline. When malformed AMPDU frames are received, the driver's state machine fails to properly evaluate the initial conditions of the first AMPDU packet in a sequence. This particular failure occurs within a specific range of sequence numbers that triggers an incorrect state transition, causing legitimate packets to be dropped rather than properly handled or discarded. The flaw demonstrates poor state management and inadequate boundary condition checking within the wireless frame processing logic.
The operational impact of this vulnerability becomes particularly pronounced during active network sessions with high traffic loads, especially during critical security operations such as pairwise rekey processes. Under these conditions, the probability of encountering malformed AMPDU frames increases significantly due to the complexity of managing encrypted traffic streams and the timing of key rotation events. When this condition occurs, it results in unintended packet drops that can cascade into complete disconnection from the access point, effectively disrupting network connectivity for affected devices.
This vulnerability aligns with CWE-248, representing an improper exception handling scenario where the wireless driver fails to properly manage exceptional conditions during frame processing. The issue also maps to ATT&CK technique T1566.002, as it represents a method of network disruption that can be leveraged to cause service availability issues in wireless networks. The specific nature of the flaw suggests potential exploitation through traffic manipulation or network congestion attacks that could force the driver into the problematic state transition.
The mitigation strategy implemented in the fix addresses the core issue by introducing proper initial state validation before processing malformed AMPDU frames. This approach ensures that the driver maintains correct internal state management during rekey operations and prevents the unintended packet drop behavior. The solution specifically targets the reset status logic to only execute during pairwise rekey processes, thereby avoiding unnecessary state transitions that could trigger the vulnerability. This defensive programming approach aligns with secure coding practices for wireless networking components and demonstrates proper resource management during critical security operations.
The fix represents a targeted correction that preserves normal wireless functionality while addressing the specific edge case in frame processing logic. It maintains backward compatibility for legitimate network operations while preventing the conditions that lead to disconnection events. The solution's focus on rekey-specific state management ensures that the wireless driver can handle normal network traffic without interruption while properly managing security-related transitions. This approach provides robust protection against the vulnerability while maintaining system stability and performance under typical network load conditions.