CVE-2022-48657 is a vulnerability identified in the Linux kernel specifically affecting the ARM64 architecture's CPU frequency scaling topology code. The issue arises in the function amu_fie_setup(), where a potential integer overflow can occur due to improper handling of frequency values. The function cpufreq_get_hw_max_freq() returns the maximum CPU frequency as an unsigned int in kilohertz (kHz), but this value is subsequently passed to freq_inv_set_max_ratio() as a 64-bit unsigned integer (u64) in hertz (Hz). The conversion involves multiplying the kHz value by 1000 to convert it to Hz. However, since the original value is an unsigned int, multiplying by 1000 without proper casting can cause an overflow if the frequency value is large enough. This overflow could lead to incorrect frequency calculations, potentially causing erroneous CPU frequency scaling behavior. The vulnerability was discovered by the Linux Verification Center using the SVACE static analysis tool and has been addressed by modifying the multiplication to use 1000ULL, ensuring the multiplication is done in 64-bit arithmetic to prevent overflow. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations running Linux systems on ARM64 hardware, this vulnerability could lead to incorrect CPU frequency scaling, which might cause performance degradation, increased power consumption, or system instability. While it does not directly enable privilege escalation or remote code execution, the mismanagement of CPU frequency could indirectly affect system reliability and availability, especially in environments relying on precise power and performance management such as data centers, telecommunications infrastructure, and embedded systems. Organizations with ARM64-based Linux deployments in critical infrastructure or industrial control systems might experience operational disruptions if this vulnerability is exploited or triggered unintentionally. However, since no active exploits are known, the immediate risk is low but should not be ignored given the potential for future exploitation or impact on system stability.

To mitigate this vulnerability, organizations should promptly apply the Linux kernel updates that include the fix for CVE-2022-48657. Specifically, ensure that the kernel version in use incorporates the patch that changes the multiplication to use 1000ULL, preventing overflow. For environments where immediate patching is challenging, monitoring CPU frequency scaling behavior and system logs for anomalies related to CPU performance could help detect potential issues. Additionally, organizations should maintain robust testing procedures for kernel updates in ARM64 environments to verify that frequency scaling operates correctly post-patch. For embedded or specialized systems, coordinate with hardware vendors to ensure firmware and kernel compatibility with the fix. Finally, maintain an inventory of ARM64 Linux systems to prioritize patch deployment based on criticality and exposure.