CVE-2025-22003 is a vulnerability identified in the Linux kernel's CAN (Controller Area Network) subsystem, specifically within the ucan driver component. The issue arises from an out-of-bounds read caused by improper use of the strscpy() function. The vulnerability was introduced when a commit replaced strncpy() with strscpy() to copy strings more securely. However, strscpy() reads up to len + 1 bytes from the source buffer to detect truncation, which leads to a one-byte out-of-bounds read if the source string is not null-terminated. In this case, the source buffer is not guaranteed to be null-terminated, causing the kernel to read beyond the allocated memory boundary. This flaw occurs during the handling of firmware strings retrieved via usb_control_msg() in the ucan driver. The root cause is the lack of immediate null-termination of the source buffer after usb_control_msg() returns, which allows the out-of-bounds read to occur. The fix involves ensuring the source buffer is null-terminated immediately and refactoring the code to handle string termination properly. Although the vulnerability results in an out-of-bounds read rather than a write, it can potentially lead to information disclosure or kernel memory leakage. There are no known exploits in the wild at this time, and the vulnerability affects specific Linux kernel versions containing the problematic commit. The vulnerability does not require user interaction but does require local access to the affected kernel subsystem, typically through device interaction with CAN hardware or virtual CAN interfaces.

For European organizations, the impact of CVE-2025-22003 depends largely on their use of Linux systems with CAN interfaces, which are common in automotive, industrial control, and embedded systems sectors. The vulnerability could allow an attacker with local access or the ability to interact with CAN devices to read kernel memory beyond intended boundaries. This may lead to leakage of sensitive kernel data, potentially aiding further privilege escalation or information gathering for more sophisticated attacks. Organizations operating critical infrastructure, automotive manufacturing, or industrial automation in Europe could face risks if their Linux-based systems with CAN support are unpatched. While the vulnerability does not directly allow code execution or denial of service, the information disclosure could be leveraged in multi-stage attacks. Given the widespread use of Linux in European IT infrastructure and embedded systems, unpatched systems could be targeted for reconnaissance or lateral movement within networks. However, exploitation requires specific conditions, including access to CAN devices, which somewhat limits the attack surface to specialized environments.

European organizations should prioritize patching Linux kernels to versions that include the fix for CVE-2025-22003. Specifically, they should update to kernel versions that ensure proper null-termination of buffers in the ucan driver and avoid the out-of-bounds read. For environments where immediate patching is not feasible, organizations should restrict access to CAN devices and interfaces, limiting them to trusted users and processes only. Implementing strict access controls and monitoring CAN device usage can reduce exploitation risk. Additionally, organizations should audit their use of CAN interfaces in embedded and industrial systems, ensuring firmware and drivers are up to date. Security teams should also monitor kernel logs for unusual activity related to CAN devices and consider deploying kernel integrity monitoring tools to detect anomalous behavior. For high-security environments, isolating CAN device interactions within sandboxed or containerized environments may further reduce risk. Finally, raising awareness among developers and system administrators about safe string handling practices in kernel code can prevent similar issues in the future.