{"id":"CVE-2026-89707","title":"kernel: nfsd: release path refs on follow_down() error (CVE-2026-89707)","summary":"A flaw was found in the Linux kernel's nfsd component. An authenticated Network File System (NFS) client can exploit this vulnerability by triggering a failed cross-mount operation through `nfsd_lookup_dentry` or the NFSv4 READDIR encode p…","severity":"high","cvss":7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","cwe":"CWE-911","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 6","enterprise_linux 7","enterprise_linux 8","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-15","sourceUpdated":"2026-09-15T12:46:55+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89707.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89707.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89707"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532441"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89707"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89707"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89707.mbox"},{"url":"https://git.kernel.org/stable/c/085cfde7c2186acaad103f02d2c25435ad5224e9"},{"url":"https://git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be"},{"url":"https://git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224"},{"url":"https://git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2"},{"url":"https://git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00603,"epssPercentile":0.47252,"scores":{"vendor":7,"cna":7.5},"ingestedAt":"2026-09-14T15:23:07.449Z","slug":"CVE-2026-89707","body":"## Overview\n\nA flaw was found in the Linux kernel's nfsd component. An authenticated Network File System (NFS) client can exploit this vulnerability by triggering a failed cross-mount operation through `nfsd_lookup_dentry` or the NFSv4 READDIR encode path. This leads to a reference count leak, which inflates `mnt_count` and `d_count`, blocking unmounting operations and pinning directory entries against the shrinker. This can result in a Denial of Service (DoS) condition.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89707.json)\n\n**kernel: nfsd: release path refs on follow_down() error** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nOut of support scope","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":203880,"id":"CVE-2026-89707","ts":1789490210646,"field":"cvss","old":"7.5","new":"7"},{"seq":197708,"id":"CVE-2026-89707","ts":1789384318495,"field":"cvss","old":"5.3","new":"7.5"},{"seq":197707,"id":"CVE-2026-89707","ts":1789384318495,"field":"severity","old":"medium","new":"high"},{"seq":183343,"id":"CVE-2026-89707","ts":1789356674964,"field":"cvss","old":"7.5","new":"5.3"},{"seq":183342,"id":"CVE-2026-89707","ts":1789356674964,"field":"severity","old":"high","new":"medium"},{"seq":153594,"id":"CVE-2026-89707","ts":1789285351420,"field":"cvss","old":null,"new":"7.5"},{"seq":153593,"id":"CVE-2026-89707","ts":1789285351420,"field":"severity","old":"none","new":"high"},{"seq":147201,"id":"CVE-2026-89707","ts":1789270200821,"field":"cvss","old":null,"new":"5.3"},{"seq":147200,"id":"CVE-2026-89707","ts":1789270200821,"field":"severity","old":"none","new":"medium"},{"seq":108954,"id":"CVE-2026-89707","ts":1789183729718,"field":"cvss","old":null,"new":"5.3"},{"seq":108953,"id":"CVE-2026-89707","ts":1789183729718,"field":"severity","old":"none","new":"medium"}]}