CVE-2026-97439

Received Received - Intake

NULL Pointer Dereference in Linux Kernel NTFS3 Filesystem

Publication date: 2026-09-24

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: preserve non-DOS attribute bits in system.dos_attrib [BUG] A corrupted ntfs3 image can hit a NULL function pointer call in generic_perform_write() after toggling system.ntfs_attrib and then overwriting system.dos_attrib on the same file. BUG: kernel NULL pointer dereference, address: 0000000000000000 \#PF: supervisor instruction fetch in kernel mode \#PF: error_code(0x0010) - not-present page PGD bed5067 P4D bed5067 PUD 0 Oops: Oops: 0010 [#1] SMP KASAN NOPTI RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffff88801025f988 EFLAGS: 00010246 Call Trace: generic_perform_write+0x409/0x8c0 mm/filemap.c:4255 __generic_file_write_iter+0x1bb/0x200 mm/filemap.c:4372 ntfs_file_write_iter+0xcd9/0x1c20 fs/ntfs3/file.c:1253 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x63b/0xf70 fs/read_write.c:686 ksys_write+0x133/0x250 fs/read_write.c:738 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x77/0xc0 fs/read_write.c:746 ... [CAUSE] system.ntfs_attrib updates ATTR_DATA flags via ni_new_attr_flags() and switches i_mapping->a_ops to ntfs_aops_cmpr when FILE_ATTRIBUTE_COMPRESSED is set. system.dos_attrib then overwrites ni->std_fa from a one-byte DOS attribute value, clearing the compression bit without updating ATTR_DATA or the mapping operations. Old buffered writes use is_compressed(ni) to choose __generic_file_write_iter(). That leaves generic_perform_write() calling a NULL write_begin callback from ntfs_aops_cmpr. [FIX] Treat system.dos_attrib as a low-byte DOS attribute update and preserve the existing non-DOS attribute bits in ni->std_fa. This keeps compressed and sparse state consistent with ATTR_DATA and the mapping operations while keeping the existing DOS attribute semantics intact.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-24

Last Modified

2026-10-03

Generated

2026-10-15

AI Q&A

2026-09-24

EPSS Evaluated

2026-10-13

NVD

CVE-2026-97439

EUVD

EUVD-2026-86052

Affected Vendors & Products

Vendor	Product	Version / Range
linux	kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability in the NTFS3 filesystem driver. It occurs when a corrupted NTFS image causes a NULL pointer dereference in generic_perform_write() after modifying system.ntfs_attrib and system.dos_attrib attributes on the same file. The bug stems from inconsistent handling of attribute flags where system.dos_attrib overwrites compression state without updating related metadata, leading to a crash when the kernel tries to access a NULL function pointer.

Detection Guidance

This vulnerability is specific to the Linux kernel's NTFS3 filesystem and requires a corrupted NTFS3 image to trigger. Detection involves checking for kernel oops or NULL pointer dereference errors in system logs after operations involving system.ntfs_attrib and system.dos_attrib on the same file. Monitor logs for messages like 'kernel NULL pointer dereference' or 'Oops: 0010' in dmesg or /var/log/kern.log.

Impact Analysis

This vulnerability could cause system crashes (kernel oops) when working with corrupted NTFS filesystems. It may lead to data corruption or loss if the system becomes unstable. Users might experience sudden reboots or filesystem errors when performing write operations on NTFS volumes.

Compliance Impact

This vulnerability is a kernel-level issue in the Linux NTFS3 filesystem driver that could lead to a NULL pointer dereference, causing system crashes or potential denial-of-service conditions. It does not directly relate to data confidentiality, integrity, or access controls typically addressed by GDPR or HIPAA. However, system instability from such vulnerabilities could indirectly impact compliance by disrupting logging, audit trails, or data processing operations.

Mitigation Strategies

Apply the latest Linux kernel update that includes the fix for this NTFS3 vulnerability. Avoid using system.ntfs_attrib and system.dos_attrib on the same file in NTFS3 filesystems until patched. If corruption is suspected, restore from a known good backup and avoid further writes to the affected filesystem.

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