Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-09-11T00:00:00 kernel: nfsd: restore rq_status_counter to even on all nfsd_dispatch() exit paths 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: restore rq_status_counter to even on all nfsd_dispatch() exit paths nfsd_dispatch() sets rq_status_counter to an odd value once a request has been decoded, and back to an even value once it has been fully processed, forming a seq-lock like protocol with the lockless reader in nfsd_nl_rpc_status_get_dumpit(). Only the fully successful path restored the counter to even. The cache-hit (RC_REPLY), drop (RC_DROPIT / RQ_DROPME) and encode-error paths all return after the odd-valued store without ever bringing the counter back to even. Once one of those paths is taken, rq_status_counter is left odd: the next request's decode ORs in 1 (still odd) and only a subsequent successful encode restores even. While stuck odd, the dumpit reader treats the rqstp fields as stable and its retry check compares against the same unchanging odd value, so it never detects concurrent mutation. This exposes actively mutating fields (e.g. args->ops / args->opcnt during compound decode and release) to the lockless reader, which can read past the end of the 8-element inline ops array. Add a helper that advances the counter to the next even value and call it on every return path that follows the odd-valued store. The decode-error path is left untouched as it is reached before the counter is set odd.

A flaw was found in the Linux kernel's Network File System (NFS) daemon, nfsd. This vulnerability occurs due to a synchronization issue where a status counter (rq_status_counter) is not correctly reset on all exit paths within the nfsd_dispatch() function. This can lead to a race condition where a lockless reader accesses actively changing data, potentially reading beyond the intended memory boundary. An attacker could exploit this memory corruption to cause a denial of service or potentially disclose sensitive information.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 10 Affected kernel-rt Red Hat Enterprise Linux 6 Not affected 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-2026-89705 https://nvd.nist.gov/vuln/detail/CVE-2026-89705 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89705.mbox