CVE-2024-27051 is a vulnerability identified in the Linux kernel specifically related to the cpufreq subsystem for the Broadcom STB (brcmstb) platform's adaptive voltage scaling (avs) CPU frequency driver. The issue arises because the function cpufreq_cpu_get, which is used to obtain a CPU frequency policy structure, may return a NULL pointer under certain conditions. The vulnerable code did not properly check the return value of cpufreq_cpu_get before dereferencing it, which could lead to a NULL pointer dereference. This results in a kernel crash (denial of service) or potentially other undefined behavior. The vulnerability was discovered by the Linux Verification Center using static analysis tools (SVACE). The fix involves adding a check for the NULL return value from cpufreq_cpu_get and returning 0 (indicating failure) if the pointer is NULL, thereby preventing the NULL dereference. This vulnerability affects Linux kernel versions containing the brcmstb-avs-cpufreq driver code prior to the patch. No known exploits are reported in the wild at this time, and no CVSS score has been assigned yet. The vulnerability is a robustness issue in kernel driver code that could be triggered by malformed or unexpected conditions in the CPU frequency scaling subsystem on affected hardware platforms using the Broadcom STB SoC. While it does not appear to allow privilege escalation or arbitrary code execution, it can cause system instability or denial of service due to kernel crashes.

For European organizations, the impact of CVE-2024-27051 primarily concerns systems running Linux kernels with the affected brcmstb-avs-cpufreq driver enabled, which is specific to Broadcom STB SoCs. These are typically embedded or specialized devices such as set-top boxes or network appliances. The direct impact is a potential denial of service via kernel crashes, which could disrupt critical services or infrastructure relying on such devices. While the vulnerability does not currently have known exploits and does not appear to enable privilege escalation, the risk of system instability could affect availability of services. Organizations using Linux-based embedded systems with Broadcom STB hardware in their network or operational technology environments should be aware of this issue. Given the limited scope of affected hardware, the impact on mainstream Linux servers or desktops is minimal. However, disruption in embedded devices used in telecommunications, media delivery, or industrial control systems could have operational consequences. The vulnerability does not compromise confidentiality or integrity directly but could be leveraged in denial-of-service attacks against targeted devices.

To mitigate CVE-2024-27051, organizations should: 1) Identify Linux systems running kernels with the brcmstb-avs-cpufreq driver enabled, particularly embedded devices using Broadcom STB SoCs. 2) Apply the official Linux kernel patches that add the NULL pointer check in cpufreq_cpu_get as soon as they become available from trusted Linux distributions or kernel maintainers. 3) For embedded devices that do not receive regular kernel updates, coordinate with device vendors to obtain firmware updates incorporating the patch. 4) Implement monitoring for kernel crashes or system instability on affected devices to detect potential exploitation attempts or triggering conditions. 5) Restrict access to management interfaces of embedded devices to reduce the risk of triggering the vulnerability remotely. 6) Employ network segmentation to isolate vulnerable embedded systems from critical infrastructure where possible. 7) Maintain an inventory of affected hardware and track vendor advisories for further updates or mitigations. These steps go beyond generic advice by focusing on identifying specific hardware platforms and ensuring patching or vendor coordination for embedded devices, which are often overlooked in standard patch management.