{"id":"CVE-2026-99111","published":"2026-10-28T11:17:30.520","lastModified":"2026-10-28T11:17:30.520","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).","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/4d143608a0445443a85c9b29f4c9f8e63d5dbfc9","tags":[]},{"url":"https://git.kernel.org/stable/c/a8603b52b39f520ea8a34def74c23fba87396d3e","tags":[]},{"url":"https://git.kernel.org/stable/c/ffa66fdc7d35b890606767c4d2c7ac26b4d90a99","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}