CVE Catalog

CVE-2026-99108

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel NTFS filesystem, ntfs_trim_fs() aligns the start of a free extent up to the discard granularity but derives the discard length by aligning the original extent length down. When the extent start is not discard-aligned, the resulting discard range can extend past the free extent into allocated clusters, which get zeroed.

Risk Assessment

A FITRIM operation can irreversibly zero data in allocated clusters adjacent to a free extent, causing data loss. The issue affects systems with mismatched discard granularity alignment.

Recommendation

Update the Linux kernel to a version with the fix that aligns the absolute end of the extent down and skips extents without a full discard unit. Until patched, avoid running FITRIM on NTFS filesystems with mismatched alignment.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ntfs: fix FITRIM range alignment ntfs_trim_fs() aligns the start of a free extent up to the device discard granularity, but derives the discard length by aligning the original extent length down. When the free extent start is not discard-aligned, adding that length to the aligned start can extend the discard past the free extent and into allocated clusters. For example, with 4 KiB clusters and 32 KiB discard granularity, the free extent [4 KiB, 36 KiB) becomes the discard range [32 KiB, 64 KiB), so 28 KiB beyond the free extent may be discarded. Align the absolute end of the free extent down and derive the length from the two aligned endpoints. Skip extents that contain no full discard unit. Reproduced with a 4 KiB-cluster NTFS filesystem on scsi_debug configured for 32 KiB discard granularity and read-zero-after-trim. Before this change, FITRIM zeroed seven allocated 4 KiB clusters following an unaligned 32 KiB hole. With this change, the same data remains intact across FITRIM and remount.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS