CVE-2024-56556 is a high-severity use-after-free (UAF) vulnerability in the Linux kernel's binder driver, specifically within the binder_add_freeze_work() function. The binder driver facilitates inter-process communication (IPC) in Android and other Linux-based systems. The vulnerability arises due to a race condition involving lock management: binder_add_freeze_work() iterates over proc->nodes while holding proc->inner_lock, but temporarily releases this lock to acquire node->lock following lock nesting order. This temporary release allows binder_node_release() to free the node concurrently, leading to a use-after-free condition when binder_add_freeze_work() later accesses the freed node. The kernel's Kernel Address Sanitizer (KASAN) detected this issue as a slab-use-after-free error during a freeze operation. Exploitation could allow an attacker with limited privileges (local access with low privileges) to execute arbitrary code or cause denial of service by corrupting kernel memory, affecting confidentiality, integrity, and availability. The fix involves taking a temporary reference on the node before releasing proc->inner_lock, ensuring the node remains valid during use and preventing the race condition. This vulnerability affects Linux kernel versions prior to the patch and is relevant to systems using the binder driver, including many Android devices and Linux distributions that support binder IPC.

For European organizations, this vulnerability poses a significant risk especially for those relying on Linux-based infrastructure or Android devices in their operational environment. Exploitation could lead to privilege escalation or kernel-level code execution, potentially allowing attackers to bypass security controls, access sensitive data, or disrupt critical services. Organizations using Linux servers with binder support or managing fleets of Android devices could face increased risk of targeted attacks or malware leveraging this vulnerability. The high impact on confidentiality, integrity, and availability means that critical systems could be compromised, leading to data breaches, operational downtime, or further lateral movement within networks. Given the widespread use of Linux in enterprise environments and Android in mobile devices, the vulnerability could affect a broad range of sectors including finance, healthcare, telecommunications, and government agencies across Europe.

European organizations should prioritize patching affected Linux kernel versions as soon as updates become available from their Linux distribution vendors. Since the vulnerability requires local access with low privileges, organizations should also enforce strict access controls and limit user privileges to reduce the attack surface. Employing kernel hardening techniques such as Kernel Address Sanitizer (KASAN) in testing environments can help detect similar issues proactively. For Android device fleets, ensure timely OS updates and consider mobile device management (MDM) solutions to enforce patch compliance. Network segmentation and monitoring for unusual binder-related system calls or kernel errors can aid in early detection of exploitation attempts. Additionally, organizations should review and tighten policies around software installation and execution on Linux systems to prevent unauthorized code execution that could exploit this vulnerability.