{"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":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-772","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":"2026-10-21","sourceUpdated":"2026-10-21T09:32:44+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://kernelcve.org/list/?q=CVE-2026-89707"},{"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":0.00612,"epssPercentile":0.49084,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T19:26:16.926763Z"},"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 2026-10-21 · [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 2026-10-21.\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\n\nWorkarounds / mitigations:\n\n- Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":227007,"id":"CVE-2026-89707","ts":1792584982823,"field":"cvss","old":"7.5","new":"6.5"},{"seq":227006,"id":"CVE-2026-89707","ts":1792584982823,"field":"severity","old":"high","new":"medium"},{"seq":223236,"id":"CVE-2026-89707","ts":1792180026527,"field":"cvss","old":"7","new":"7.5"},{"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"}]}