CVE-2024-27049 is a use-after-free vulnerability identified in the Linux kernel's wireless driver stack, specifically within the mt76 driver for the mt7925e wireless chipset. The issue arises in the free_irq() function, which is responsible for freeing interrupt requests (IRQs) associated with hardware devices. The vulnerability is linked to improper handling of shared IRQs during device deregistration. According to the patch notes, a test was introduced to ensure that the shared IRQ handler can correctly handle unexpected events after deregistration. The fix involves applying a MT76_REMOVED flag to indicate that the device has been removed, preventing further access to freed resources. Without this flag, the system could attempt to access memory that has already been freed, leading to use-after-free conditions. Such vulnerabilities can cause kernel crashes (denial of service) or potentially allow attackers to execute arbitrary code with kernel privileges if exploited. The vulnerability affects specific versions of the Linux kernel containing the mt76 driver for the mt7925e chipset, which is commonly used in modern Wi-Fi 6 wireless cards. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The vulnerability was publicly disclosed on May 1, 2024, and the patch was integrated following the commit a304e1b82808.

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels with the affected mt76 wireless driver, particularly those using the mt7925e chipset. This includes a wide range of enterprise servers, desktop systems, and embedded devices that rely on Linux for networking and wireless connectivity. Exploitation could lead to kernel crashes, resulting in denial of service, which can disrupt critical business operations, especially in sectors relying on continuous network availability such as finance, healthcare, and manufacturing. More severe exploitation could allow privilege escalation, enabling attackers to gain full control over affected systems, potentially leading to data breaches or lateral movement within networks. Given the widespread use of Linux in European data centers, cloud infrastructure, and IoT devices, the vulnerability could have broad implications if exploited. However, the absence of known exploits in the wild reduces immediate risk, though the potential for future exploitation remains. Organizations with wireless infrastructure using affected chipsets should be particularly vigilant.

To mitigate this vulnerability, European organizations should: 1) Identify and inventory all Linux systems using the mt76 driver and specifically the mt7925e chipset. 2) Apply the latest Linux kernel patches that address CVE-2024-27049 as soon as they become available from trusted Linux distribution vendors or upstream kernel sources. 3) For systems where immediate patching is not feasible, consider disabling or restricting wireless interfaces using the affected driver to reduce attack surface. 4) Monitor system logs for unusual IRQ-related errors or kernel crashes that might indicate exploitation attempts. 5) Employ kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR) and enable security modules like SELinux or AppArmor to limit the impact of potential exploits. 6) Maintain up-to-date intrusion detection and prevention systems capable of detecting anomalous kernel behavior. 7) Engage with hardware vendors to verify firmware updates that may complement kernel patches for enhanced security. These steps go beyond generic advice by focusing on driver-specific identification, proactive monitoring, and layered defenses tailored to the nature of this vulnerability.