CVE-2022-49137 is a vulnerability identified in the Linux kernel specifically within the AMD GPU driver subsystem (drm/amd/amdgpu). The flaw resides in the function amdgpu_cs_fence_to_handle_ioctl(), which handles certain ioctl commands related to command submission fences. When the input parameter info->in.what falls into an unexpected default case, the function returns an error code (-EINVAL) without properly decrementing the reference count of a dma_fence object. This dma_fence object’s reference count had been incremented earlier by amdgpu_cs_get_fence(). The failure to decrement the reference count leads to a reference count leak, which is a form of resource leak. Over time, this can cause the kernel to hold onto dma_fence objects longer than necessary, potentially exhausting kernel memory or other resources associated with these objects. The vulnerability is triggered in an error path, meaning it occurs when invalid or unexpected input is processed. The fix involves explicitly decrementing the reference count of the dma_fence object before returning the error code, ensuring proper resource cleanup. This vulnerability does not appear to allow direct code execution or privilege escalation but can degrade system stability and reliability by leaking kernel resources. No known exploits are reported in the wild, and no CVSS score has been assigned yet. The affected versions are specific Linux kernel commits identified by their hashes, indicating this is a recent and targeted fix in the AMD GPU driver codebase.

For European organizations, the impact of CVE-2022-49137 primarily concerns system stability and availability. Organizations running Linux systems with AMD GPUs, especially those using workloads that heavily interact with the GPU via the amdgpu driver (e.g., graphics-intensive applications, compute workloads, or virtualization environments), may experience gradual degradation of system performance or unexpected crashes due to resource exhaustion caused by the reference count leak. This could affect data centers, cloud providers, research institutions, and enterprises relying on Linux servers or workstations with AMD GPUs. Although this vulnerability does not directly compromise confidentiality or integrity, the resulting denial of service or system instability can disrupt critical operations, leading to downtime and potential financial losses. Since the issue arises from an error path, it may be triggered by malformed or unexpected ioctl calls, which could be exploited by local users or malicious software with access to the system. Therefore, the threat is more relevant in environments where untrusted users or applications have access to the GPU driver interfaces. The absence of known exploits reduces immediate risk, but the vulnerability should be addressed proactively to maintain system reliability.

To mitigate CVE-2022-49137, European organizations should: 1) Apply the official Linux kernel patches that fix the reference count leak in the amdgpu driver as soon as they become available from trusted Linux distributions or the kernel maintainers. 2) Ensure that all Linux systems using AMD GPUs are running updated kernel versions that include this fix. 3) Limit access to GPU device interfaces (e.g., /dev/dri/*) to trusted users and processes only, reducing the risk of triggering the error path through malicious ioctl calls. 4) Monitor system logs and kernel messages for signs of resource leaks or unusual GPU driver errors that could indicate attempts to exploit this vulnerability. 5) Implement robust system resource monitoring to detect early signs of kernel memory exhaustion or performance degradation related to GPU driver issues. 6) In virtualized or containerized environments, restrict GPU passthrough or access to trusted workloads to minimize exposure. 7) Engage with Linux distribution vendors or security mailing lists to stay informed about updates and advisories related to this vulnerability.