CVE-2021-47196

A flaw was found in the Linux kernel's RDMA (Remote Direct Memory Access) core subsystem. When creating a communication endpoint known as a Queue Pair, the kernel does not properly set the send and receive completion queue pointers before invoking the hardware driver. If endpoint creation fails, the subsequent error handling cleanup references invalid memory, triggering a use-after-free condition. A local user can exploit this vulnerability to crash the kernel, resulting in a Denial of Service (DoS).

This vulnerability is rated as Low severity because exploitation requires local access, specialized RDMA network hardware, and an induced failure during endpoint setup, restricting the impact to a localized denial of service. Standard Red Hat Enterprise Linux installations are rarely exposed, as Remote Direct Memory Access (RDMA) and InfiniBand subsystems are typically utilized only in specialized high-performance computing or dedicated clustering environments. Furthermore, triggering the flaw requires access to RDMA user verbs interfaces and hardware-specific drivers such as mlx5.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.