CVE-2026-89715

A low impact flaw was found in the Linux kernel's NFS local I/O (localio) support, affecting OpenShift Container Platform versions 5.0 and 5.1 through the RHEL CoreOS 9 kernel. When nfs_uuid_add_file() races with nfs_uuid_put() during network namespace teardown, the error path of nfsd_open_local_fh() fails to release a caller-owned nfsd_file reference and its paired nfsd_net reference. Each occurrence of this race leaks kernel resources, pinning a struct file, dentry, and inode, and blocks nfsd_net and network namespace teardown, so repeated triggering can exhaust resources and cause a denial of service. Exploitation requires an NFS client using localio to race local file handle setup against namespace teardown, and only availability is affected; Red Hat Product Security therefore rates the impact as Low even though the Red Hat CVSS 3.1 base score is 5.5 (Moderate). Red Hat Enterprise Linux kernel releases are not affected because the vulnerable localio code, introduced upstream in the 6.17 kernel, is not present in them, and earlier OpenShift 4.x releases are likewise not affected. For the affected OpenShift 5.0 and 5.1 releases the fix has been deferred to a future update; the residual risk is limited to gradual resource exhaustion and blocked network namespace teardown on nodes using NFS localio, with no impact on confidentiality or integrity.