CVE-2022-49267 is a vulnerability identified in the Linux kernel's MMC (MultiMediaCard) core subsystem. The issue arises from the use of the unsafe function sprintf() for sysfs output generation. Specifically, sprintf() is used to format strings for sysfs entries, which are virtual files used to expose kernel information to user space. The vulnerability is a buffer overflow risk because sprintf() does not perform bounds checking on the output buffer, potentially allowing an attacker to overflow the buffer and corrupt adjacent memory. The vulnerability was discovered by the Linux Verification Center using the SVACE static analysis tool, highlighting a coding practice flaw rather than an externally reported exploit. The fix involves replacing sprintf() with sysfs_emit(), a safer function designed for sysfs output that includes proper buffer size checks to prevent overflow. The affected versions are identified by a specific commit hash, indicating the vulnerability is present in certain Linux kernel versions prior to the patch. No known exploits are reported in the wild, and no CVSS score has been assigned yet. The vulnerability affects the Linux kernel, which is widely used across various distributions and devices, including servers, desktops, embedded systems, and cloud infrastructure. Because the vulnerability is in the kernel's MMC subsystem, it specifically impacts systems that interact with MMC devices or expose MMC-related information via sysfs. The risk is primarily related to local privilege escalation or denial of service if an attacker can trigger the buffer overflow through crafted sysfs interactions, potentially leading to kernel memory corruption.

For European organizations, the impact of CVE-2022-49267 depends on the deployment of vulnerable Linux kernel versions and the exposure of MMC sysfs interfaces. Organizations running Linux servers, embedded devices, or infrastructure components that utilize MMC storage or expose sysfs interfaces could be at risk. Successful exploitation could lead to kernel memory corruption, causing system instability, crashes, or potentially privilege escalation if combined with other vulnerabilities. This could disrupt critical services, especially in sectors relying heavily on Linux-based infrastructure such as finance, telecommunications, manufacturing, and government. The absence of known exploits reduces immediate risk, but the vulnerability's presence in widely deployed Linux kernels means that attackers could develop exploits over time. European organizations with strict regulatory requirements for system integrity and uptime (e.g., GDPR, NIS Directive) must consider this vulnerability seriously to avoid compliance issues and operational disruptions.

To mitigate CVE-2022-49267, European organizations should: 1) Identify Linux systems running affected kernel versions by checking kernel commit hashes or vendor advisories. 2) Apply the official Linux kernel patches that replace sprintf() with sysfs_emit() in the MMC core as soon as they become available from trusted sources or Linux distribution maintainers. 3) For systems where immediate patching is not feasible, restrict access to sysfs MMC interfaces to trusted users only, minimizing the risk of local exploitation. 4) Implement strict access controls and monitoring on systems with MMC devices to detect unusual sysfs interactions or kernel errors. 5) Incorporate this vulnerability into vulnerability management and patching cycles, ensuring timely updates. 6) Engage with Linux distribution vendors for backported patches if using long-term support kernels. 7) Conduct thorough testing of kernel updates in staging environments to prevent service disruptions. These steps go beyond generic advice by focusing on sysfs interface access control, vendor coordination, and operational testing specific to this vulnerability.