{"id":"CVE-2026-98684","revision":"7e8b82c6e0f643ca8fb7de761f664e85","records":[{"revision":"7e8b82c6e0f643ca8fb7de761f664e85","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98684","aliases":[],"title":"smb: client: flush and commit data before querying allocated ranges","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: flush and commit data before querying allocated ranges\n\nThe mode 0 / FALLOC_FL_KEEP_SIZE fallocate emulation for small interior\nranges in smb3_simple_fallocate_range() issues\nFSCTL_QUERY_ALLOCATED_RANGES and zero-fills any sub-range the server\nreports as an unallocated hole, to force block allocation without\nchanging file contents.\n\nThis is unsafe against Windows servers.  Per the Win32 documentation,\nFSCTL_QUERY_ALLOCATED_RANGES only reports ranges that *may* contain\nnonzero data and is explicitly not coherent with recently written data:\n\n  \"a call to FSCTL_QUERY_ALLOCATED_RANGES [after writing to a network\n   file] would not necessarily return a correct list of allocated\n   regions.  To ensure coherency [...] flush the data to the file\"\n\nfsx (generic/363) reproduces the resulting corruption against Windows\nServer 2022: a range is written, an uncached read returns the data, yet\nthe next FSCTL_QUERY_ALLOCATED_RANGES on that range reports it as a whole\nhole, so the emulation overwrites live data with zeroes.  A network trace\nconfirmed the WRITE, the READ returning data and the query returning an\nempty range list within microseconds.  Samba does not exhibit this; its\nquery is coherent with the written data.\n\nWrite back the dirty pages, drain any outstanding I/O and issue an SMB2\nFLUSH to force the server to commit the data before querying the\nallocated ranges, so the query reflects the data actually present.\n\nWith this, generic/363 passes against both Windows Server 2022 and Samba\nover 100000 fsx operations.","state":0,"publishedAt":"2026-10-18T15:45:52.828+00:00","modifiedAt":"2026-10-19T09:23:54.479+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/smb/client/smb2ops.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"966a3cb7c7db786452a87afdc3b48858fc4d4d6b\",\n                            \"lessThan\": \"f82242fe3109a3ef72f429540b5bdde08fbfb0e4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"966a3cb7c7db786452a87afdc3b48858fc4d4d6b\",\n                            \"lessThan\": \"bf84e44ff0ed802778eafd7ecb623635379cb506\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"966a3cb7c7db786452a87afdc3b48858fc4d4d6b\",\n                            \"lessThan\": \"aa994489bd835547c191827acc460192e147032d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c406bb9ece6ef63721daab106f132ff4b4234e81\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2f9f4a2d0e6fcf0673ed51195e06e47abe966900\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5e397c943424de94879830e72c95f2679e297a76\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.10.50\",\n                            \"lessThan\": \"5.11\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.12.17\",\n                            \"lessThan\": \"5.13\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.13.2\",\n                            \"lessThan\": \"5.14\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\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/smb/client/smb2ops.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.56\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.10\",\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":[],"references":["https://git.kernel.org/stable/c/f82242fe3109a3ef72f429540b5bdde08fbfb0e4","https://git.kernel.org/stable/c/bf84e44ff0ed802778eafd7ecb623635379cb506","https://git.kernel.org/stable/c/aa994489bd835547c191827acc460192e147032d"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98684","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98684","identifiers":["CVE-2026-98684"]},"retained":false,"historicalAffected":[]}],"coverage":[]}