CVE-2022-49210 is a vulnerability identified in the Linux kernel specifically affecting the MIPS architecture's page allocation subsystem. The issue arises from improper handling of the pgd (Page Global Directory) table memory deallocation. The Linux kernel introduced a generic implementation of pgd_free() to free pgd pages, but this implementation assumes that only one page is allocated for the pgd table. However, in certain configurations—such as when PAGE_SIZE_4KB is enabled and MIPS_VA_BITS_48 is not enabled on a 64-bit MIPS system—the pgd table consists of more than one page (specifically two pages due to PGD_ORDER being set to 1). The generic pgd_free() function frees only one page, leaving the other page allocated and causing a memory leak. This leak can be observed by continuously running commands that allocate and free memory, for example, "while true; do ls > /dev/null; grep MemFree /proc/meminfo; done". Although this vulnerability does not directly allow code execution or privilege escalation, the memory leak can degrade system performance over time, potentially leading to resource exhaustion and system instability. The vulnerability is specific to certain MIPS configurations and does not affect all Linux kernel deployments. There are no known exploits in the wild, and no CVSS score has been assigned yet. The issue was published on February 26, 2025, and is addressed by kernel patches that correct the pgd_free() implementation to properly free all allocated pgd pages in affected configurations.

For European organizations, the impact of CVE-2022-49210 is primarily related to system stability and availability rather than direct compromise of confidentiality or integrity. Organizations using Linux systems on MIPS architecture with the specific kernel configurations mentioned are at risk of memory leaks that could degrade performance, cause unexpected crashes, or require frequent reboots to recover memory. This is particularly relevant for embedded systems, network devices, or specialized industrial equipment that rely on MIPS-based Linux kernels. In sectors such as telecommunications, manufacturing, or critical infrastructure where such devices may be deployed, prolonged memory leaks could lead to service interruptions or degraded operational efficiency. However, since the vulnerability does not enable remote code execution or privilege escalation, the risk of direct cyberattacks exploiting this flaw is low. The absence of known exploits in the wild further reduces immediate threat levels. Nonetheless, the potential for denial-of-service conditions due to resource exhaustion means that organizations should prioritize patching affected systems to maintain reliability and uptime.

To mitigate CVE-2022-49210, organizations should: 1) Identify all Linux systems running on MIPS architecture, especially those with 64-bit kernels configured with PAGE_SIZE_4KB enabled and MIPS_VA_BITS_48 disabled. 2) Apply the latest Linux kernel patches that address the pgd_free() memory leak. If official patches are not yet available, consider backporting fixes from the mainline kernel or applying vendor-provided updates. 3) Monitor system memory usage closely on affected devices to detect abnormal memory consumption trends indicative of leaks. 4) Implement automated alerts for memory exhaustion thresholds to enable proactive intervention before service disruption occurs. 5) For embedded or network devices where kernel updates are challenging, consider system restarts as a temporary mitigation to reclaim leaked memory, while planning for firmware or kernel upgrades. 6) Engage with hardware and software vendors to confirm patch availability and deployment timelines. 7) Document and test patch deployment procedures in controlled environments to avoid unintended downtime. These steps go beyond generic advice by focusing on architecture-specific identification, proactive monitoring, and vendor coordination.