{"id":"CVE-2026-89679","revision":"103ccb7d60d1407c8bdad44dac0172db","records":[{"revision":"103ccb7d60d1407c8bdad44dac0172db","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89679","aliases":[],"title":"nfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs\n\nWhen a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or\nFATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr()\nsets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate\nthe stateid.\n\nIf the client supplies the NFSv4 \"one stateid\" (all-0xFF bytes),\ncheck_special_stateids() returns nfs_ok without populating the output\nnfs4_stid pointer, because the special-stateid path in\nnfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the\n\"if (s)\" block that would set *cstid is skipped. The local variable `st`\nremains NULL.\n\nBack in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally\ndereferences st->sc_type (at offset 4 from NULL), causing a kernel oops.\n\nThis is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH,\nSETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})].\nNo authentication, delegation, or prior state is required.\n\nFix by adding a NULL check before the dereference. A special stateid is\nnot a delegation stateid, so the existing nfserr_bad_stateid return value\nis already correct; we only need to guard the pointer dereference itself.","state":0,"publishedAt":"2026-09-11T19:46:02.833+00:00","modifiedAt":"2026-10-19T08:50:52.556+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/nfs4proc.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7e13f4f8d27dc02fb88666f603c53ca749d56f92\",\n                            \"lessThan\": \"3c5119b799a7f57db332b2c31e806de16c869f0f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e13f4f8d27dc02fb88666f603c53ca749d56f92\",\n                            \"lessThan\": \"3c896db123892256fd39af0ee8c2d02c63539983\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7e13f4f8d27dc02fb88666f603c53ca749d56f92\",\n                            \"lessThan\": \"fe456c8c0931bb3e8a03d429920e87fd85747fba\",\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/nfs4proc.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\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:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/3c5119b799a7f57db332b2c31e806de16c869f0f","https://git.kernel.org/stable/c/3c896db123892256fd39af0ee8c2d02c63539983","https://git.kernel.org/stable/c/fe456c8c0931bb3e8a03d429920e87fd85747fba"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89679","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89679","identifiers":["CVE-2026-89679"]},"retained":false,"historicalAffected":[]}],"coverage":[]}