{"id":"CVE-2026-99111","aliases":[],"title":"smb: client: fix data corruption with concurrent writes and O_TRUNC","titleSource":"Linux","descriptionSource":"Linux","products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"110fee6b9bb58a5c50047fc2594d415f741b591e","status":"affected","lessThan":"4d143608a0445443a85c9b29f4c9f8e63d5dbfc9","versionType":"git"},{"version":"110fee6b9bb58a5c50047fc2594d415f741b591e","status":"affected","lessThan":"ffa66fdc7d35b890606767c4d2c7ac26b4d90a99","versionType":"git"},{"version":"110fee6b9bb58a5c50047fc2594d415f741b591e","status":"affected","lessThan":"a8603b52b39f520ea8a34def74c23fba87396d3e","versionType":"git"}],"defaultStatus":"unaffected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99111"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"6.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.18","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99111"}],"remediation":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix data corruption with concurrent writes and O_TRUNC\n\ncifs_do_truncate() flushes dirty pages with filemap_write_and_wait()\nand truncates the file on the server, but in the old code both\noperations ran without holding i_rwsem or invalidate_lock.  A\nconcurrent buffered write via netfs_perform_write() -- which only\nneeds i_rwsem shared -- could dirty new pages after the flush but\nbefore the local truncation, and those pages would be silently\ndiscarded by cifs_setsize() -> truncate_pagecache().\n\nFix by acquiring inode_lock (exclusive i_rwsem) and\nfilemap_invalidate_lock at the top of cifs_do_truncate(), so the\nentire flush-truncate-resize sequence is atomic with respect to:\n\n  - buffered writes (blocked by exclusive i_rwsem, since\n    netfs_start_io_write takes i_rwsem shared),\n  - read page faults (blocked by exclusive invalidate_lock, since\n    filemap_fault takes it shared),\n  - writeback collection (blocked by netfs_wb_begin/netfs_wb_end\n    around the server truncate and local resize, since\n    netfs_writepages also acquires the wb lock).","severity":"unknown","score":null,"published":"2026-10-28T10:34:29.053Z","modified":"2026-10-28T10:34:29.053Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://git.kernel.org/stable/c/4d143608a0445443a85c9b29f4c9f8e63d5dbfc9","https://git.kernel.org/stable/c/ffa66fdc7d35b890606767c4d2c7ac26b4d90a99","https://git.kernel.org/stable/c/a8603b52b39f520ea8a34def74c23fba87396d3e"],"sources":[{"name":"CVE","id":"CVE-2026-99111","modified":"2026-10-28T10:34:29.053Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-99111"}],"assessments":[],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-29T05:05:31.777Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}