Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-09-11T00:00:00 kernel: nfsd: clear opcnt on compound arg release to prevent OOB read 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-125

In the Linux kernel, the following vulnerability has been resolved: nfsd: clear opcnt on compound arg release to prevent OOB read nfsd4_release_compoundargs() resets args->ops to the inline iops[8] array when the dynamically-allocated ops buffer is freed, but leaves args->opcnt at its original value (which can be up to 200 for NFSv4.1+ compounds). If rq_status_counter is stuck at an odd value (which can happen when nfsd_dispatch() hits an error path after setting it odd), the RPC status dumpit handler reads min(opcnt, 16) entries from args->ops[]. Since iops only has 8 elements and is the last field in struct nfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory and leaks it to userspace via netlink. Zero opcnt unconditionally in nfsd4_release_compoundargs() so stale compound metadata is never exposed through the status interface. [ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ]

A flaw was found in the Linux kernel's Network File System Daemon (nfsd) component. The nfsd4_release_compoundargs() function does not properly clear an internal counter (opcnt) when releasing a buffer. This oversight can lead to an out-of-bounds read, allowing an attacker to access adjacent memory and potentially leak sensitive information to userspace through netlink.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 10 Affected kernel-rt Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt Red Hat OpenShift Container Platform 4 Not affected openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 4 Affected openshift/ose-rhel-coreos-9 https://www.cve.org/CVERecord?id=CVE-2026-89691 https://nvd.nist.gov/vuln/detail/CVE-2026-89691 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89691.mbox