CVE-2026-99242

In the Linux kernel, the following vulnerability has been resolved:

ntfs: fix race between fallocate and mmap reads

The fallocate implementation only takes invalidate lock for punch hole, collapse range, and insert range operations. For standard allocation modes (mode == 0, FALLOC FL KEEP SIZE), the lock is not held.

During ntfs attr fallocate(), new clusters are mapped to the runlist via ntfs attr map cluster() before being zeroed by ntfs dio zero range(). This creates a window where concurrent mmap page faults can read uninitialized disk data.

Since mmap uses filemap fault() which takes invalidate lock in shared mode, it can fault in pages during this window and expose old disk contents to userspace. This is an information leak and data integrity issue.

Fix by taking invalidate lock for all fallocate operations, not just for punch/collapse/insert modes. This prevents concurrent page faults from accessing unzeroed clusters during the allocation window.