CVE-2024-42148 is a vulnerability identified in the Linux kernel's Broadcom bnx2x network driver, specifically affecting the handling of Ethernet queues in NICs using the E1x and E2 controllers. The vulnerability arises from an out-of-bounds read/write on the array "struct stats_query_entry query" within the "bnx2x_fw_stats_req" structure. This array's size is defined based on the macro FP_SB_MAX_E1x (value 16) plus an offset BNX2X_FIRST_QUEUE_QUERY_IDX (value 3), resulting in a total size of 19. However, the driver supports NICs with the E2 controller that can handle more queues, represented by FP_SB_MAX_E2, which is larger than FP_SB_MAX_E1x. The driver incorrectly limits the array size to the E1x maximum, causing accesses beyond the allocated array bounds when more queues are configured, leading to undefined behavior and potential memory corruption. The root cause is a mismatch between the array size and the number of Ethernet queues supported by the hardware, especially when the number of queues exceeds the E1x limit but is within the E2 capabilities. The vulnerability manifests as UBSAN (Undefined Behavior Sanitizer) array-index-out-of-bounds warnings and can cause kernel crashes or unpredictable behavior. The issue is triggered when systems have 32 or more physical CPU cores or when the user sets the num_queues module parameter to a value equal or greater than FP_SB_MAX_E1x. The patch to fix this vulnerability involves increasing the array size by replacing FP_SB_MAX_E1x with FP_SB_MAX_E2, ensuring the array can accommodate the maximum number of queues supported by both E1x and E2 NICs. This vulnerability is specific to Linux kernel versions containing the affected bnx2x driver code and impacts systems using Broadcom NICs with E1x or E2 controllers. It does not require user interaction but depends on system configuration and hardware capabilities. No known exploits are reported in the wild as of the publication date.

For European organizations, this vulnerability poses a risk primarily to servers and network infrastructure using Linux systems equipped with Broadcom bnx2x network interface cards, especially those with E2 controllers supporting high numbers of Ethernet queues. The out-of-bounds access can lead to kernel instability, crashes, or potential memory corruption, which could disrupt network connectivity and availability of critical services. In environments with high-performance networking requirements, such as data centers, cloud providers, and telecom operators, this could degrade service reliability and increase downtime. Although no direct remote code execution or privilege escalation is indicated, the instability caused by this vulnerability could be exploited by an attacker with local access or through crafted network configurations to cause denial of service. This is particularly concerning for European organizations relying on Linux-based infrastructure for essential services, including financial institutions, healthcare providers, and government agencies. The vulnerability's impact on confidentiality and integrity is limited, but availability could be significantly affected if exploited or triggered inadvertently. Given the widespread use of Linux in enterprise and cloud environments across Europe, and the popularity of Broadcom NICs in server hardware, the potential for operational disruption is notable. Organizations with large-scale deployments or high core-count servers are at increased risk due to the conditions that trigger the vulnerability.

1. Apply the official Linux kernel patches that address CVE-2024-42148 as soon as they become available from trusted sources or Linux distribution vendors. This patch increases the array size to accommodate the maximum number of Ethernet queues supported by the hardware. 2. Audit and limit the number of Ethernet queues configured via the num_queues module parameter to not exceed the safe limits (i.e., FP_SB_MAX_E1x or FP_SB_MAX_E2 as appropriate) until patches are applied. 3. Monitor kernel logs for UBSAN warnings or related error messages indicating out-of-bounds access in the bnx2x driver to detect potential triggering of the vulnerability. 4. For systems with Broadcom NICs using the E2 controller, prioritize patching due to higher risk from increased queue support. 5. Implement strict access controls to limit local administrative access to systems, reducing the risk of exploitation by unauthorized users. 6. Test kernel updates in staging environments to ensure compatibility and stability before deployment in production. 7. Maintain up-to-date hardware and driver inventories to identify affected systems accurately. 8. Collaborate with hardware vendors and Linux distribution maintainers to receive timely updates and advisories related to this vulnerability.