CVE-2021-47149 is a vulnerability identified in the Linux kernel, specifically within the network driver code for Fujitsu hardware (fmvj18x). The issue arises in the function fmvj18x_get_hwinfo(), where a failure in the ioremap() call is not properly handled. ioremap() is a kernel function used to map physical memory addresses into the kernel's virtual address space. If ioremap() fails, it returns NULL, and subsequent dereferencing of this NULL pointer leads to a null pointer dereference vulnerability. This can cause the kernel to crash (kernel panic), leading to a denial of service (DoS) condition. The fix involves adding a check for the return value of ioremap() and returning an error code (-1) to the caller if the mapping fails, thereby preventing the NULL pointer dereference. This vulnerability is specific to certain versions of the Linux kernel that include the vulnerable Fujitsu network driver code. There are no known exploits in the wild, and no CVSS score has been assigned yet. The vulnerability affects the availability of systems running the affected Linux kernel versions with this driver, but does not directly compromise confidentiality or integrity. Exploitation requires triggering the vulnerable code path, which may require specific hardware or conditions, and likely requires local or privileged access to the system to invoke the driver functionality.

For European organizations, the primary impact of CVE-2021-47149 is the potential for denial of service on Linux systems running the affected kernel versions with the Fujitsu network driver. This could disrupt critical network services, leading to downtime and operational impact. Organizations relying on Linux servers for networking, especially those using Fujitsu hardware or embedded systems with this driver, may experience system crashes or instability. While this vulnerability does not appear to allow privilege escalation or data compromise, the availability impact could affect service continuity, incident response, and business operations. In sectors such as telecommunications, finance, healthcare, and critical infrastructure, even short outages can have significant consequences. The lack of known exploits reduces immediate risk, but unpatched systems remain vulnerable to accidental or malicious triggering of the bug. European organizations with strict uptime requirements and regulatory obligations around service availability should prioritize patching to mitigate potential disruptions.

1. Apply the official Linux kernel patches that address CVE-2021-47149 as soon as they become available from trusted sources or Linux distribution vendors. 2. Identify and inventory systems running affected Linux kernel versions, particularly those using Fujitsu network hardware or drivers. 3. If immediate patching is not possible, consider temporarily disabling or unloading the vulnerable Fujitsu network driver module to prevent triggering the vulnerability. 4. Implement monitoring to detect kernel panics or crashes related to network driver failures, enabling rapid incident response. 5. Restrict access to systems running the vulnerable driver to trusted users and networks to reduce the risk of accidental or malicious exploitation. 6. Test patches in staging environments to ensure compatibility and stability before deployment in production. 7. Maintain up-to-date backups and recovery plans to minimize downtime impact in case of exploitation. 8. Engage with hardware vendors and Linux distribution maintainers for guidance and updates specific to affected hardware models.