CVE-2022-48708 is a vulnerability identified in the Linux kernel's pin control subsystem, specifically within the 'pinctrl: single' driver. The issue arises from a missing NULL pointer check in the function pcs_set_mux(). The function pinmux_generic_get_function() can return a NULL pointer, but the returned pointer 'function' was dereferenced without verifying if it was NULL. This can lead to a potential NULL pointer dereference, which may cause the kernel to crash (kernel panic) or result in undefined behavior. The vulnerability was discovered by the Linux Verification Center using static analysis tools (SVACE). The root cause is a lack of defensive programming in handling pointer returns from pinmux_generic_get_function(), leading to an unsafe dereference. The vulnerability affects specific Linux kernel versions identified by commit hashes, indicating it is present in certain recent kernel builds prior to the fix. No known exploits are reported in the wild, and no CVSS score has been assigned yet. The fix involves adding a proper NULL check before dereferencing the pointer, preventing the kernel from crashing due to this condition.

For European organizations, this vulnerability could impact any systems running the affected Linux kernel versions, especially those using the pin control subsystem in embedded devices, IoT, or specialized hardware relying on pin multiplexing. A NULL pointer dereference in the kernel typically leads to a denial of service (DoS) via system crash or reboot. While this does not directly lead to privilege escalation or data leakage, the availability impact can be significant for critical infrastructure, industrial control systems, or servers requiring high uptime. Systems that rely on Linux kernels with this vulnerability may experience unexpected downtime, affecting business continuity. Since the vulnerability does not require user interaction or authentication, an attacker with local access or the ability to trigger the vulnerable code path could cause a denial of service. However, remote exploitation likelihood is low unless the vulnerable code is exposed via network services or drivers. European organizations with embedded Linux devices in sectors like manufacturing, telecommunications, or transportation could be particularly affected if these devices run vulnerable kernels.

Organizations should promptly identify Linux systems running the affected kernel versions by checking kernel commit hashes or version numbers corresponding to the vulnerable code. Applying the official Linux kernel patches that add the NULL pointer check in pcs_set_mux() is the primary mitigation. For embedded or custom Linux distributions, rebuild kernels with the fix included. Additionally, implement monitoring for kernel crashes or unexpected reboots that could indicate exploitation attempts. Restrict local access to trusted users and limit exposure of vulnerable devices to untrusted networks. For critical systems, consider deploying kernel hardening techniques and enabling kernel crash dumps to facilitate forensic analysis. Regularly update Linux kernels to the latest stable releases to benefit from security fixes. Vendors of embedded devices should release updated firmware incorporating the patched kernel. Finally, conduct security audits on custom kernel modules or drivers that interact with pin control to ensure similar issues are not present.