CVE-2025-37796 is a vulnerability identified in the Linux kernel specifically affecting the at76c50x wireless driver component. The flaw arises from a use-after-free condition in the at76_disconnect function. During the execution of at76_delete_device, the memory referenced by the 'priv' pointer is freed using ieee80211_free_hw. However, subsequent code erroneously accesses the 'udev' field of this already freed memory object to handle the USB device. This improper memory access can lead to undefined behavior including potential memory corruption and instability of the kernel module. Additionally, the flaw may cause a memory leak related to the USB device structure. The root cause is improper handling of the USB device pointer after the associated memory has been freed. The fix involves modifying the code to use the 'udev' pointer from the interface context rather than from the freed 'priv' object, thereby preventing access to invalid memory. This vulnerability is present in specific Linux kernel versions identified by the commit hash 29e20aa6c6aff35c81d4da2e2cd516dadb569061 and was publicly disclosed on May 1, 2025. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability impacts the kernel's wireless USB device handling, which is a critical component for systems using at76c50x wireless chipsets.

For European organizations, this vulnerability poses a risk primarily to systems running affected Linux kernel versions with the at76c50x wireless driver enabled. Exploitation could lead to kernel instability, crashes, or potentially privilege escalation if an attacker can trigger the use-after-free condition remotely or locally. This could disrupt wireless connectivity, impacting business operations reliant on Wi-Fi access, especially in environments using embedded Linux devices or specialized hardware with this chipset. Confidentiality and integrity could be compromised if attackers leverage this flaw to execute arbitrary code or escalate privileges. Availability may also be affected due to system crashes or memory leaks. Although no active exploits are known, the vulnerability's presence in the Linux kernel—a widely used OS in European enterprises, government, and critical infrastructure—means that exploitation could have broad consequences. The impact is heightened in sectors with high reliance on wireless connectivity and Linux-based embedded systems, such as telecommunications, manufacturing, and public services.

European organizations should promptly update their Linux kernel to the patched version that addresses CVE-2025-37796. Since the vulnerability is in the kernel wireless driver, kernel updates from trusted Linux distributions should be applied as soon as they become available. For environments where immediate patching is not feasible, disabling or unloading the at76c50x wireless driver can mitigate risk, though this may reduce wireless functionality. Network segmentation and strict access controls should be enforced to limit exposure of vulnerable devices to untrusted networks. Monitoring kernel logs for unusual crashes or memory errors related to the wireless driver can help detect exploitation attempts. Organizations should also review their asset inventory to identify devices using the at76c50x chipset and prioritize patching accordingly. Employing endpoint detection and response (EDR) solutions capable of detecting anomalous kernel behavior may provide additional protection. Finally, maintaining up-to-date backups and incident response plans will help mitigate impact in case of exploitation.