CVE-2024-41077 is a vulnerability identified in the Linux kernel's null_blk module, which is responsible for a block device emulation that maps to memory. The issue arises from improper validation of the block size parameter (bs). The Linux kernel expects the block size to be a power of two and to fall within the range between 512 bytes and the system's PAGE_SIZE. However, prior to the patch, the validation logic did not enforce these constraints correctly. Specifically, an invalid block size such as 1536 bytes (which is not a power of two) could be passed without triggering an error. This improper validation leads to a null pointer dereference (null pointer deref) when the null_blk module is loaded with such an invalid block size, causing the kernel to Oops (kernel panic or crash). The patch fixes this by updating the validation checks to ensure the block size is within the valid range and is a power of two, preventing the null pointer dereference and subsequent kernel crash. The vulnerability does not appear to have known exploits in the wild at this time, and no CVSS score has been assigned yet. The affected versions are identified by a specific commit hash, indicating the vulnerability exists in recent Linux kernel versions prior to the patch. This vulnerability is a denial-of-service (DoS) type, as it causes the kernel to crash, impacting system availability.

For European organizations, the primary impact of CVE-2024-41077 is the potential for denial-of-service conditions on Linux systems that utilize the null_blk module, particularly in environments where block devices are emulated or virtualized. This could affect cloud service providers, data centers, and enterprises running Linux-based servers or virtualized infrastructure. A kernel crash can lead to service interruptions, data loss in volatile memory, and operational downtime, which can be critical for industries relying on high availability such as finance, healthcare, telecommunications, and government services. Although exploitation requires loading the null_blk module with a crafted block size parameter, this may be feasible in environments where untrusted users have the ability to load kernel modules or configure block devices, such as multi-tenant cloud platforms or containerized environments with elevated privileges. The lack of known exploits reduces immediate risk, but the vulnerability should be addressed promptly to prevent potential future exploitation. Confidentiality and integrity impacts are minimal since the vulnerability primarily causes a crash rather than arbitrary code execution or privilege escalation.

European organizations should apply the official Linux kernel patch that corrects the block size validation in the null_blk module as soon as it becomes available in their distribution's kernel updates. Until patched, organizations should restrict the ability to load kernel modules to trusted administrators only, minimizing the risk of malicious or accidental loading of null_blk with invalid parameters. System administrators should audit and monitor kernel module loading activities and block device configurations for anomalies. In containerized or virtualized environments, ensure that container runtimes and hypervisors do not allow unprivileged users to load kernel modules or manipulate block device parameters. Additionally, organizations should implement robust kernel crash monitoring and automated recovery mechanisms to reduce downtime in case of unexpected Oops events. Regularly updating Linux kernels and subscribing to security advisories from Linux distributions and the Linux kernel mailing list will help maintain awareness and timely patching of this and similar vulnerabilities.