CVE-2024-56691 is a vulnerability identified in the Linux kernel specifically related to the mfd (multi-function device) driver for the Intel SoC PMIC (Power Management IC) BXTWC, which manages USB Type-C device interrupts. The issue stems from an improper implementation of IRQ (Interrupt Request) domain handling within the driver. The design intent was to convert the driver to use a hierarchical IRQ chip structure, which is a correct architectural approach. However, the implementation inherited flaws that cause incorrect handling of IRQ numbers, particularly when platform_get_irq() triggers warnings on IRQ 0, which is expected to be a valid Linux IRQ number (vIRQ). The root cause is the failure to respect the IRQ domain boundaries when creating each MFD device separately, as the IRQ domain is not uniform across all devices. This can lead to incorrect interrupt routing or handling, potentially causing system instability or malfunction of USB Type-C related hardware components. The vulnerability affects specific Linux kernel versions identified by commit hashes, and no known exploits are currently reported in the wild. The issue was resolved by reworking the driver to correctly respect IRQ domains for each MFD device, ensuring proper interrupt management and system stability.

For European organizations, the impact of CVE-2024-56691 could be significant in environments relying on Linux-based systems with Intel SoC PMIC BXTWC hardware, particularly those using USB Type-C interfaces extensively. Potential impacts include system instability, unexpected device malfunctions, or denial of service conditions due to improper interrupt handling. This could affect critical infrastructure, enterprise servers, embedded systems, and industrial control systems that depend on reliable USB Type-C connectivity for power delivery or data transfer. While no active exploits are known, the vulnerability could be leveraged by attackers to disrupt operations or cause hardware communication failures, impacting confidentiality, integrity, and availability indirectly through system crashes or degraded performance. Organizations with high reliance on Linux kernel stability and Intel SoC platforms should consider this vulnerability a risk to operational continuity and hardware reliability.

European organizations should prioritize updating their Linux kernels to versions that include the fix for CVE-2024-56691. Specifically, they should apply patches that rework the mfd:intel_soc_pmic_bxtwc driver to correctly handle IRQ domains per MFD device. System administrators should audit their Linux systems to identify the presence of affected kernel versions and Intel SoC PMIC BXTWC hardware. For embedded and industrial systems, firmware updates incorporating the patched kernel should be deployed promptly. Additionally, organizations should implement monitoring for kernel warnings related to IRQ handling, such as WARN() messages triggered by platform_get_irq(), to detect potential exploitation or malfunction. Testing updates in controlled environments before production deployment is recommended to ensure stability. As a precaution, organizations should maintain robust backup and recovery procedures to mitigate potential disruptions caused by this vulnerability.