CVE-2022-49059 is a high-severity use-after-free (UAF) vulnerability identified in the Linux kernel's NFC (Near Field Communication) subsystem, specifically within the NCI (NFC Controller Interface) device handling code. The flaw arises due to a race condition between concurrent threads managing the lifecycle of an NCI device. When detaching an NCI device, the cleanup routine calls del_timer_sync() to remove a timer (cmd_timer), assuming it has been fully detached. However, a worker thread can concurrently re-arm this timer via mod_timer() even after the device memory has been freed (kfree(ndev)), leading to a use-after-free condition. This race is triggered by the interplay between timer and workqueue mechanisms, where the delayed execution of workqueue tasks causes unexpected scheduling. The vulnerability is demonstrated by kernel crash logs showing KASAN (Kernel Address Sanitizer) detecting a write to freed memory during enqueue_timer operations. The flaw affects Linux kernel versions including the commit 6a2968aaf50c7a22fced77a5e24aa636281efca8 and likely others in the 5.x and 6.x series. Exploitation requires local privileges (PR:L) but no user interaction (UI:N), and the attack vector is local (AV:L). The impact includes full compromise of confidentiality, integrity, and availability of the affected system due to potential arbitrary code execution or kernel crashes. No known exploits are currently reported in the wild, but the vulnerability is easy to trigger given the race condition nature. The flaw is categorized under CWE-416 (Use After Free). The Linux vendor has resolved this issue by adding flush_workqueue calls to ensure proper synchronization and prevent the race condition. The CVSS v3.1 base score is 7.8, reflecting high severity with high impact on confidentiality, integrity, and availability.

For European organizations, this vulnerability poses a significant risk especially for those relying on Linux-based systems with NFC capabilities, such as embedded devices, IoT gateways, industrial control systems, and mobile devices running Linux kernels vulnerable to this flaw. Exploitation can lead to kernel crashes causing denial of service or privilege escalation to root, enabling attackers to gain full control over affected systems. This can compromise sensitive data, disrupt critical services, and potentially serve as a foothold for lateral movement within networks. Organizations in sectors like manufacturing, healthcare, transportation, and finance that deploy Linux-based infrastructure with NFC components are particularly at risk. The local attack vector means that attackers need some level of access, but insider threats or compromised user accounts could leverage this vulnerability to escalate privileges. The lack of user interaction requirement increases the risk of automated exploitation once local access is obtained. Given the widespread use of Linux in European IT environments and the increasing adoption of NFC technologies, the vulnerability could impact a broad range of systems if unpatched.

1. Immediate application of the official Linux kernel patches that address CVE-2022-49059 is critical. Organizations should track kernel updates from their Linux distribution vendors and deploy them promptly. 2. For environments where immediate patching is not feasible, consider disabling NFC functionality or unloading the NFC kernel modules (e.g., nci, nfcmrvl) to eliminate the attack surface. 3. Implement strict access controls and monitoring on systems with NFC capabilities to prevent unauthorized local access, including limiting user privileges and employing endpoint detection and response (EDR) solutions to detect anomalous kernel activity. 4. Use kernel hardening features such as Kernel Address Space Layout Randomization (KASLR), Kernel Page Table Isolation (KPTI), and SELinux/AppArmor policies to reduce exploitation likelihood. 5. Conduct thorough audits of systems with NFC hardware to identify vulnerable kernel versions and NFC usage. 6. Employ network segmentation and zero-trust principles to limit lateral movement from compromised hosts. 7. Maintain comprehensive logging and alerting for kernel crashes or suspicious workqueue/timer activity that could indicate exploitation attempts.