CVE-2023-52644 is a vulnerability identified in the Linux kernel's wireless networking subsystem, specifically affecting the Broadcom b43 wireless driver and the mac80211 stack. The issue arises when Quality of Service (QoS) is disabled in the wireless configuration. Under these conditions, the queue priority value does not correctly map to the ieee80211 queue because only a single queue is instantiated. The vulnerability manifests as an incorrect attempt to stop or wake a non-existent queue, leading to failure in managing the actual queue in use. This results in kernel warnings and potentially unstable behavior, as evidenced by kernel logs showing warnings and stack traces related to __ieee80211_wake_queue in mac80211. The root cause is a logic flaw in queue management when QoS is disabled, causing the driver to interact with queue 0 incorrectly. The vulnerability has been addressed by modifying the driver to stop and wake queue 0 explicitly when QoS is disabled, preventing attempts to manipulate non-existent queues. The affected Linux kernel versions include those identified by the commit hash e6f5b934fba8c44c87c551e066aa7ca6fde2939e. There is no indication that this vulnerability has been exploited in the wild, and no CVSS score has been assigned yet. The issue primarily affects systems using the b43 wireless driver, which supports certain Broadcom wireless chipsets, commonly found in older or embedded Linux systems. The vulnerability could lead to system instability or denial of service conditions due to improper queue handling in the wireless driver.

For European organizations, the impact of CVE-2023-52644 depends largely on the deployment of affected Linux systems using the b43 wireless driver. Organizations relying on Linux servers, desktops, or embedded devices with Broadcom wireless chipsets that use this driver and have QoS disabled may experience system instability or kernel warnings that could degrade wireless network performance or cause temporary denial of service. This could affect operational continuity, especially in environments where wireless connectivity is critical. While this vulnerability does not directly lead to privilege escalation or remote code execution, the resulting instability could disrupt services or user productivity. Industries with significant Linux usage in networking equipment, IoT devices, or embedded systems—such as telecommunications, manufacturing, and critical infrastructure—may be more exposed. The lack of known exploits reduces immediate risk, but unpatched systems remain vulnerable to potential future exploitation or accidental system failures. The impact is mitigated if QoS is enabled or if alternative wireless drivers are used. However, given the widespread use of Linux in European IT environments, particularly in public sector, research institutions, and technology companies, the vulnerability warrants prompt attention to avoid service disruptions.

To mitigate CVE-2023-52644, European organizations should: 1) Identify Linux systems using the b43 wireless driver by auditing kernel modules and hardware inventories, focusing on devices with Broadcom wireless chipsets. 2) Verify whether QoS is disabled on these systems; enabling QoS where feasible can prevent the incorrect queue mapping issue. 3) Apply the latest Linux kernel updates or patches that include the fix for this vulnerability, specifically those incorporating the commit e6f5b934fba8c44c87c551e066aa7ca6fde2939e or later. 4) For embedded or specialized devices where kernel updates are not straightforward, consider vendor firmware updates or workarounds that enable QoS or disable the affected driver if not in use. 5) Monitor system logs for kernel warnings related to ieee80211 queue management to detect potential exploitation or instability. 6) Implement network segmentation and access controls to limit exposure of vulnerable wireless devices. 7) Engage with hardware vendors for support on updated drivers or firmware. These steps go beyond generic advice by focusing on driver-specific and configuration-based mitigations tailored to the vulnerability's nature.