CVE-2026-72185: Undefined Security Weakness

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

ntfs: fix WARN_ON for resident attribute in ntfs_map_runlist_nolock()

When ntfs_map_runlist_nolock() needs to look up the attribute extent containing a target VCN (ctx_needs_reset == true), it calls ntfs_attr_lookup() and then expects the result to be a non-resident attribute, since only non-resident attributes have a mapping pairs array to decompress.

A crafted NTFS image can place a resident attribute where a non-resident one is expected, causing ntfs_attr_lookup() to succeed but return a resident attribute record. Previously this was caught only by a WARN_ON(), which does not stop execution. The code then falls through to read a->data.non_resident.highest_vcn from what is actually a resident attribute, accessing the wrong union member and corrupting the VCN range check.

The caller path triggering this warning during mount is:

ntfs_map_runlist_nolock ntfs_empty_logfile load_system_files ntfs_fill_super

In this path ctx is NULL, so ntfs_map_runlist_nolock() allocates a temporary search context internally and sets ctx_needs_reset = true. The existing resident-attribute guard in the ctx != NULL branch already returns -EIO silently for the same condition; make the ctx_needs_reset path consistent by replacing the WARN_ON() with the same -EIO error return.

This causes the crafted image to be rejected with a mount error instead of triggering a kernel warning.