{"id":"CVE-2026-98124","summary":"smb/client: invalidate fscache for fallocate range operations","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb/client: invalidate fscache for fallocate range operations\n\nsmb3_zero_range(), smb3_punch_hole(), smb3_insert_range(), and\nsmb3_collapse_range() modify file contents through server-side range\noperations. These operations discard the affected page cache, but leave\nthe FS-Cache cookie valid, so a later read may return data cached before\nthe range operation.\n\nFix this by invalidating FS-Cache after outstanding I/O has completed\nand before modifying the file on the server.\n\nRun the following as root on a CIFS mount with fsc enabled and an active\nCacheFiles backend:\n\n        bash -c '\n                MNT=/mnt/cifs\n                FILE=\"$MNT/repro\"\n\n                # Generate four 1 MiB random blocks: [A][B][C][D].\n                dd if=/dev/urandom of=/tmp/src bs=1M count=4 status=none\n\n                # Expected contents after zeroing B: [A][zero][C][D].\n                cp /tmp/src /tmp/expected\n                dd if=/dev/zero of=/tmp/expected bs=1M seek=1 count=1 \\\n                        conv=notrunc status=none\n                cp /tmp/src \"$FILE\"\n\n                # Populate FS-Cache, then discard the page cache.\n                sync\n                echo 1 \u003e /proc/sys/vm/drop_caches\n                cat \"$FILE\" \u003e /dev/null\n                sync\n                echo 1 \u003e /proc/sys/vm/drop_caches\n\n                fallocate --zero-range -o 1M -l 1M \"$FILE\"\n\n                if cmp -s /tmp/expected \"$FILE\"; then\n                        echo \"readback: OK\"\n                else\n                        echo \"readback: STALE DATA\"\n                fi\n        '\n\nBefore this change, the readback differs from /tmp/expected:\n\n        readback: STALE DATA\n\nAfter this change, it matches:\n\n        readback: OK","modified":"2026-09-27T03:47:39.739285014Z","published":"2026-09-25T10:36:06.581Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98124.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/448ba0ae65ca61064183564d2983c9aa59bd6ba7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/93c6e5a8d7c5071d586c1411596d5db5faad22b2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98124.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98124"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"31742c5a331766bc7df6b0d525df00c6cd20d5a6"},{"fixed":"93c6e5a8d7c5071d586c1411596d5db5faad22b2"},{"fixed":"448ba0ae65ca61064183564d2983c9aa59bd6ba7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98124.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.17.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98124.json"}}],"schema_version":"1.9.0"}