CVE-2024-26895 is a use-after-free vulnerability identified in the Linux kernel's wireless driver for the WILC1000 WiFi chipset (wilc1000). The flaw occurs in the function wilc_netdev_cleanup, which is responsible for cleaning up network interfaces (vif) during device unbinding or module removal. Specifically, the vulnerability arises when the driver attempts to unregister net devices while traversing the vif list. Because the netdevice object is freed upon unregistration (due to the needs_free_netdev flag), the associated vif object, which is stored as private data within the netdevice, is also freed. However, the traversal loop continues to access the freed vif pointer, leading to a use-after-free condition. This is detected by Kernel Address Sanitizer (KASAN) as a slab-use-after-free error. The root cause is improper list traversal and synchronization during vif removal. The fix involves two key mechanisms: (1) using list_for_each_entry_safe to safely iterate and modify the vif list, removing elements with list_del_rcu, and (2) waiting for the Read-Copy-Update (RCU) grace period to ensure safe freeing of vif objects after unregister_netdev calls. The vulnerability is triggered during interface registration errors or when unbinding the wilc1000_spi driver, which is used primarily on embedded systems with Atmel SAMA5 hardware. While no known exploits are reported in the wild, the flaw could lead to kernel crashes or potential escalation of privileges if exploited, as use-after-free bugs can be leveraged for arbitrary code execution in kernel context. The vulnerability affects Linux kernel versions containing the wilc1000 driver prior to the fix applied in kernel version 6.8.0-rc1+ and related commits. The issue was initially investigated by David Mosberger-Tan and publicly disclosed in April 2024.

For European organizations, the impact of CVE-2024-26895 depends largely on their use of Linux-based embedded systems or devices that incorporate the WILC1000 WiFi chipset, such as industrial IoT devices, network appliances, or specialized hardware running Linux kernels vulnerable to this flaw. Exploitation could lead to denial of service via kernel crashes or potentially privilege escalation, compromising device integrity and availability. This is particularly critical for sectors relying on embedded Linux devices for operational technology (OT), manufacturing automation, or critical infrastructure, where device stability and security are paramount. Although no public exploits exist yet, the vulnerability's presence in the Linux kernel means that any organization deploying affected devices without timely patching could face increased risk of targeted attacks or malware leveraging this flaw. Additionally, the use-after-free nature of the bug could be a stepping stone for attackers to execute arbitrary code in kernel space, potentially allowing full system compromise. This risk is heightened in environments where devices are exposed to untrusted networks or users. Therefore, European enterprises with embedded Linux deployments or custom Linux kernels incorporating the wilc1000 driver should consider this vulnerability a serious threat to device security and operational continuity.

Mitigation requires applying the official Linux kernel patches that address the use-after-free in the wilc1000 driver. Organizations should: 1) Identify all devices running Linux kernels with the wilc1000 driver, especially embedded systems using Atmel SAMA5 or similar hardware. 2) Update these devices to Linux kernel versions 6.8.0-rc1+ or later where the fix is integrated, or backport the patch if using older kernel versions. 3) For devices where kernel updates are not immediately feasible, consider disabling or unloading the wilc1000_spi driver module to prevent triggering the vulnerability, recognizing this may impact WiFi functionality. 4) Implement strict access controls to prevent unauthorized unbinding or module removal operations, as these actions trigger the vulnerability. 5) Monitor kernel logs for KASAN warnings or unusual crashes related to wilc_netdev_cleanup to detect potential exploitation attempts. 6) Engage with device vendors to obtain updated firmware or kernel versions that include the fix. 7) Incorporate this vulnerability into vulnerability management and patching workflows to ensure timely remediation. These steps go beyond generic advice by focusing on embedded device inventory, kernel version management, and operational controls specific to the wilc1000 driver environment.