CVE-2022-42720 is a high-severity vulnerability affecting the mac80211 wireless stack in the Linux kernel versions from 5.1 through 5.19.x prior to 5.19.16. The vulnerability arises from multiple reference counting bugs in the multi-BSS (Basic Service Set) handling code. These bugs can lead to use-after-free conditions, a type of memory corruption where the system continues to use memory after it has been freed. Exploiting this vulnerability requires local attacker capabilities, specifically the ability to inject WLAN frames, which implies that the attacker must be within wireless range and able to interact with the affected device's wireless interface. Successful exploitation could allow an attacker to execute arbitrary code with kernel privileges, potentially leading to full system compromise. The CVSS v3.1 base score is 7.8, reflecting high impact on confidentiality, integrity, and availability, with attack vector classified as local, requiring low attack complexity and low privileges, and no user interaction. The vulnerability is categorized under CWE-416 (Use After Free). Although no known exploits are reported in the wild, the presence of a use-after-free in kernel wireless code represents a significant risk, especially for devices relying on vulnerable Linux kernel versions. No specific vendor or product is listed, but the affected component is the Linux kernel mac80211 subsystem, widely used in many Linux-based systems including servers, desktops, and embedded devices. The vulnerability was publicly disclosed on October 13, 2022, and fixed in Linux kernel version 5.19.16. No direct patch links are provided in the data, but the fix is available in the official kernel updates.

For European organizations, this vulnerability poses a substantial risk particularly to those using Linux-based systems with vulnerable kernel versions in their wireless infrastructure. This includes enterprise laptops, wireless access points, IoT devices, and embedded systems that rely on the mac80211 stack. Exploitation could lead to unauthorized code execution at the kernel level, allowing attackers to bypass security controls, escalate privileges, and potentially move laterally within networks. Confidentiality of sensitive data could be compromised, integrity of systems undermined, and availability disrupted through kernel crashes or malicious payloads. Given the local attack vector requiring WLAN frame injection, organizations with dense wireless environments or public Wi-Fi access points are at higher risk. This vulnerability could be leveraged in targeted attacks against critical infrastructure, government agencies, or enterprises with wireless-enabled Linux devices. The lack of known exploits in the wild reduces immediate risk but does not eliminate it, as attackers may develop exploits over time. The potential impact is magnified in sectors with high reliance on Linux wireless networking, such as telecommunications, manufacturing, and research institutions prevalent in Europe.

European organizations should prioritize updating Linux kernel versions to 5.19.16 or later where the vulnerability is patched. For systems where immediate kernel upgrades are not feasible, consider disabling or restricting wireless interfaces using the mac80211 stack, especially on critical systems. Employ network segmentation to isolate vulnerable wireless devices from sensitive network segments. Implement strict wireless access controls and monitoring to detect anomalous WLAN frame injection attempts. Utilize host-based intrusion detection systems (HIDS) capable of monitoring kernel integrity and unusual wireless activity. Regularly audit and inventory Linux systems to identify those running vulnerable kernel versions. For embedded or IoT devices, coordinate with vendors for firmware updates or mitigations. Additionally, applying kernel hardening techniques such as enabling Kernel Address Space Layout Randomization (KASLR), and using security modules like SELinux or AppArmor can reduce exploitation likelihood. Finally, maintain up-to-date threat intelligence feeds to monitor for emerging exploits targeting this vulnerability.