CVE-2022-49004 is a vulnerability identified in the Linux kernel specifically affecting the RISC-V architecture implementation of EFI (Extensible Firmware Interface) page table management. The EFI page table is initially created as a copy of the kernel page table. When VMAP_STACK is enabled, kernel stacks are allocated in the vmalloc area, which may involve new Page Global Directories (PGDs) that were not present or synchronized at the time of EFI page table creation. If a kernel stack is allocated in such a new PGD, the kernel may encounter a trap when switching to the EFI page table and accessing the vmalloc kernel stack, resulting in a kernel panic. This occurs because the EFI page table's kernel mappings are not updated or synchronized before the switch, leading to invalid memory access. The fix involves updating the EFI kernel mappings before switching to the EFI page table to ensure consistency and prevent the kernel panic. This vulnerability is specific to the Linux kernel on RISC-V platforms with VMAP_STACK enabled and affects kernel stability by causing a denial of service through kernel panics. There are no known exploits in the wild, and no CVSS score has been assigned yet. The vulnerability was published on October 21, 2024, and is considered resolved in updated kernel versions.

The primary impact of CVE-2022-49004 is a denial of service (DoS) condition due to kernel panics on affected Linux systems running on RISC-V architecture with VMAP_STACK enabled. For European organizations, this could disrupt critical services and infrastructure relying on such Linux systems, particularly in sectors adopting RISC-V hardware for embedded systems, IoT devices, or specialized computing environments. While RISC-V adoption is currently limited compared to x86 or ARM, its growth in industrial automation, telecommunications, and research institutions in Europe could expose these organizations to unexpected system crashes, leading to downtime, loss of availability, and potential operational disruptions. Since the vulnerability does not appear to allow privilege escalation or code execution, confidentiality and integrity impacts are minimal. However, the availability impact can be significant if exploited or triggered unintentionally, especially in environments requiring high reliability and uptime.

To mitigate CVE-2022-49004, European organizations should: 1) Ensure Linux kernel versions are updated to the latest patched releases that include the fix for this vulnerability, especially on RISC-V systems with VMAP_STACK enabled. 2) Audit and identify all RISC-V based Linux systems in their environment to assess exposure. 3) Disable VMAP_STACK if feasible and if it does not impact system functionality, as this feature is central to the vulnerability. 4) Implement robust monitoring for kernel panics and system crashes to detect potential exploitation or triggering of this issue. 5) For critical systems, consider isolating or limiting exposure of RISC-V Linux hosts until patches are applied. 6) Engage with hardware and software vendors to confirm support and patch availability for RISC-V platforms. 7) Incorporate this vulnerability into incident response and risk management frameworks to prepare for potential availability impacts.