{"id":"CVE-2026-90036","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during blocked-lock reaping\n\nA bare lock owner -- its only remaining reference a blocked lock on\nnn->blocked_locks_lru -- holds a ra…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during blocked-lock reaping\n\nA bare lock owner -- its only remaining reference a blocked lock on\nnn->blocked_locks_lru -- holds a ra…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= 7919d0a27f1e7cb324e023776aa1cbff00f1ee7b < cd489b03587378645fe0d20142a33f1ed60bac98","Linux >= 7919d0a27f1e7cb324e023776aa1cbff00f1ee7b < 6fedb2eaff77554ca7a0deffd2e8bc0d6e8b38b0","Linux >= 7919d0a27f1e7cb324e023776aa1cbff00f1ee7b < 9026932ac8be4d0ae01db47f23619a98cc57b671","Linux 4.9"],"published":"2026-09-16","updated":"2026-09-21","sourceUpdated":"2026-09-21T14:17:27.843","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90036","references":[{"url":"https://git.kernel.org/stable/c/6fedb2eaff77554ca7a0deffd2e8bc0d6e8b38b0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7081224a59a0ca4edcd62c068588f4d900199a18","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9026932ac8be4d0ae01db47f23619a98cc57b671","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cd489b03587378645fe0d20142a33f1ed60bac98","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0d53a47c913d0bce3b5ec35c28cbcca4d015f33d"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90036.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-90036"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2535158"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90036"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90036"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90036.mbox"},{"url":"https://access.redhat.com/errata/RHSA-2026:83207"},{"url":"https://access.redhat.com/errata/RHSA-2026:83156"},{"url":"https://access.redhat.com/errata/RHSA-2026:83157"},{"url":"https://access.redhat.com/errata/RHSA-2026:83159"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00484,"epssPercentile":0.41521,"ingestedAt":"2026-09-16T10:53:53.934Z","patched":["10base_smtv","enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_8","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_crb_v_8","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_hidden_v_10","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_nfv_v_8","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_v_10","enterprise_linux_rt_v_8","enterprise_linux_real_time_v_9"],"cwe":["CWE-825"],"scores":{"nvd":9.8,"vendor":8.8},"slug":"CVE-2026-90036","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during blocked-lock reaping\n\nA bare lock owner -- its only remaining reference a blocked lock on\nnn->blocked_locks_lru -- holds a raw pointer to its nfs4_client but\nno reference keeping the client alive. When the per-net laundromat\nreaps such a lock, freeing the nbl drops the owner reference\nheld through flc_owner, and the final nfs4_put_stateowner()\ntakes the client's cl_lock. Because the laundromat detaches the\nnbl first, __destroy_client() no longer finds it, so a concurrent\nforce_expire_client() can free the client before nfs4_put_stateowner()\nruns, dereferencing cl_lock in freed memory.\n\nPin the client with cl_rpc_users before dropping\nnn->blocked_locks_lock, and skip clients already expiring, whose\nblocked locks __destroy_client() frees while holding an owner\nreference. Take nn->client_lock outside nn->blocked_locks_lock.\nEvery other site holds nn->blocked_locks_lock as a leaf, acquiring\nno further lock, so placing nn->client_lock outside it cannot form\na lock-order cycle.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:83207** · Red Hat · fixed in: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Hidden (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), … · released 2026-10-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:83207)\n- **RHSA-2026:83156** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83156)\n- **RHSA-2026:83157** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83157)\n- **RHSA-2026:83159** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83159)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90036.json)","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":205001,"id":"CVE-2026-90036","ts":1789570702626,"field":"cvss","old":null,"new":"9.8"},{"seq":205000,"id":"CVE-2026-90036","ts":1789570702626,"field":"severity","old":"none","new":"critical"}]}