CVE-2026-97477

A flaw was found in the Linux kernel's Remote Direct Memory Access (RDMA) subsystem. An error-handling issue during counter allocation and queue pair binding neglects to decrement the active counter tally when a bind attempt fails. A local user can exploit this flaw by triggering repeated binding failures, which leaks counter references and permanently prevents the port from switching operational modes, resulting in a denial of service.

A low impact denial of service flaw was found in the Linux kernel's RDMA (Remote Direct Memory Access) subsystem. When binding a queue pair to a counter fails in alloc_and_bind(), the error path frees the counter without decrementing port_counter->num_counters. A local user with access to RDMA resources can trigger repeated binding failures to leak counter references, which permanently prevents the affected RDMA port from switching counter modes: switching to AUTO mode fails with -EBUSY and the automatic MANUAL-to-NONE revert is blocked. The result is a local denial of service limited to RDMA counter mode management on the affected port; confidentiality and integrity are not affected. Red Hat Product Security has rated this flaw as Low impact, which is lower than the moderate severity implied by the Red Hat CVSS 3.1 base score of 5.5 (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H), because exploitation requires local access to RDMA-capable hardware and the consequence is confined to degraded counter mode management. Affected Red Hat products include the kernel, kernel-rt, and kernel-ivos-qualcomm components as well as OpenShift RHEL CoreOS 8 and 9; certain versions are not affected because the vulnerable code is not present. Because of the low assessed impact, fixes are currently deferred for the affected products; the residual risk is a local denial of service limited to RDMA counter mode switching on affected ports.

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.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.