{"id":"CVE-2026-90036","revision":"c4b0bc7dc11447fa802042465401a752","records":[{"revision":"c4b0bc7dc11447fa802042465401a752","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90036","aliases":[],"title":"NFSD: Prevent client use-after-free during blocked-lock reaping","description":"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 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.","state":0,"publishedAt":"2026-09-16T10:33:35.967+00:00","modifiedAt":"2026-10-21T12:49:32.115+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs4state.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7919d0a27f1e7cb324e023776aa1cbff00f1ee7b\",\n                            \"lessThan\": \"0d53a47c913d0bce3b5ec35c28cbcca4d015f33d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7919d0a27f1e7cb324e023776aa1cbff00f1ee7b\",\n                            \"lessThan\": \"7081224a59a0ca4edcd62c068588f4d900199a18\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7919d0a27f1e7cb324e023776aa1cbff00f1ee7b\",\n                            \"lessThan\": \"cd489b03587378645fe0d20142a33f1ed60bac98\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7919d0a27f1e7cb324e023776aa1cbff00f1ee7b\",\n                            \"lessThan\": \"6fedb2eaff77554ca7a0deffd2e8bc0d6e8b38b0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7919d0a27f1e7cb324e023776aa1cbff00f1ee7b\",\n                            \"lessThan\": \"9026932ac8be4d0ae01db47f23619a98cc57b671\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs4state.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.9\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.9\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.160\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.111\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.51\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.5\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/0d53a47c913d0bce3b5ec35c28cbcca4d015f33d","https://git.kernel.org/stable/c/7081224a59a0ca4edcd62c068588f4d900199a18","https://git.kernel.org/stable/c/cd489b03587378645fe0d20142a33f1ed60bac98","https://git.kernel.org/stable/c/6fedb2eaff77554ca7a0deffd2e8bc0d6e8b38b0","https://git.kernel.org/stable/c/9026932ac8be4d0ae01db47f23619a98cc57b671"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90036","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90036","identifiers":["CVE-2026-90036"]},"retained":false,"historicalAffected":[]}],"coverage":[]}