CVE-2024-44981 is a vulnerability identified in the Linux kernel's workqueue subsystem, specifically related to the function shift_and_mask(). The issue arises from the use of a signed immediate value in constructing a bitmask, which leads to an integer subtraction overflow when the function is called with a shift value of 31 (defined as WORK_OFFQ_POOL_SHIFT). This causes the calculation to decrement from INT_MIN, triggering an undefined behavior sanitizer (UBSAN) error during kernel boot, particularly observable in virtual machine environments on Android. The error manifests as a kernel panic with a message indicating an integer subtraction overflow, effectively halting the system. The root cause is the use of a signed constant in bitmask generation; the fix involves changing this to an unsigned constant ('1U') to prevent the overflow. This vulnerability affects Linux kernel versions prior to the patch and is triggered during early kernel initialization, impacting the stability and availability of systems running vulnerable kernel versions. Although no known exploits are reported in the wild, the vulnerability can cause denial of service due to kernel panic, especially in virtualized environments or Android devices using affected kernels. The vulnerability does not require user interaction or authentication to trigger, as it occurs during system boot. The affected versions are identified by specific commit hashes, indicating the issue is present in certain recent kernel builds before the fix was applied.

For European organizations, the primary impact of CVE-2024-44981 is on system availability and reliability. Since the vulnerability causes kernel panics during boot, affected systems may fail to start or become unstable, leading to potential downtime. This is particularly critical for organizations relying on Linux-based virtual machines, embedded systems, or Android devices using the affected kernel versions. Industries such as telecommunications, cloud service providers, automotive, and critical infrastructure that deploy Linux kernels in virtualized or embedded environments could experience operational disruptions. The inability to boot or maintain stable operation can lead to service outages, impacting business continuity and potentially causing financial losses. Additionally, while no direct confidentiality or integrity breaches are indicated, the denial of service aspect could be exploited in targeted attacks to disrupt services. European organizations with large-scale Linux deployments, especially those using custom or older kernel versions, may face challenges in patch management and system updates to mitigate this issue promptly.

To mitigate CVE-2024-44981, European organizations should prioritize updating their Linux kernels to versions that include the fix changing the bitmask construction from a signed to an unsigned constant. This involves applying the latest stable kernel patches or vendor-provided updates that address this specific issue. For organizations using Android devices or virtual machines, ensuring that the underlying kernel is updated is critical. Additionally, system administrators should audit their environments to identify systems running vulnerable kernel versions, particularly focusing on virtualized platforms and embedded devices. Implementing robust testing procedures for kernel updates in staging environments can prevent unexpected downtime. Where immediate patching is not feasible, organizations might consider restricting deployment of affected kernel versions in production or using kernel boot parameters to disable affected workqueue features if possible, though this may reduce functionality. Monitoring system logs for UBSAN errors or kernel panics related to workqueue operations can help detect attempts to trigger this vulnerability. Finally, maintaining an inventory of Linux kernel versions across infrastructure and automating patch management will reduce exposure to such vulnerabilities.