CVE-2025-38357

A flaw was found in the Linux kernel's Fuse (Filesystem in Userspace) component. This vulnerability arises from improper handling of Direct Access (DAX) entries during filesystem operations, specifically within the truncate_folio_batch_exceptionals() function. A local attacker with low privileges could exploit this, potentially leading to high impact on data confidentiality, integrity, and system availability.

A moderate severity flaw was found in the Linux kernel FUSE (Filesystem in Userspace) component. The kernel did not properly handle DAX (Direct Access) entries in the truncate_folio_batch_exceptionals() code path during FUSE inode eviction, so leftover DAX entries could trigger a kernel runtime warning (WARN_ON_ONCE in mm/truncate.c) when a DAX-enabled FUSE filesystem is unmounted. Upstream had already fixed the equivalent issue for XFS and Ext4 in commit 0e2f80afcfa6 ("fs/dax: ensure all pages are idle prior to filesystem unmount"), and this flaw concerns the missed application of that fix to FUSE. Red Hat Product Security has rated this issue as Moderate (CVSS 6.1, CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L) because the demonstrated upstream impact is a local kernel warning rather than the broader confidentiality, integrity, and availability impact reflected in the NIST and CVE.org scores of 7.8. All Red Hat Enterprise Linux 6, 7, 8, 9, and 10 and Red Hat In-Vehicle OS kernel and kernel-rt streams have been assessed as not affected, because the vulnerable code is not present in the shipped Red Hat kernels.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.