# CVE-2026-72470: fs/ntfs3: resize log->one_page_buf when adopting on-disk page size

> A buffer overflow in the Linux kernel NTFS3 driver allows attackers to cause memory corruption and potential code execution by mounting a specially crafted dirty NTFS volume.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72470, DEBIAN-CVE-2026-72470, GHSA-mxhq-w28g-hr4q, UBUNTU-CVE-2026-72470

## What is CVE-2026-72470?

CVE-2026-72470 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: resize log->one_page_buf when adopting on-disk page size

log_replay() allocates log->one_page_buf using the page size that was
chosen from the host PAGE_SIZE:

	log->one_page_buf = kmalloc(log->page_size, GFP_NOFS);

Later, when a restart area is found, the log page size recorded on disk
is adopted:

	t32 = le32_to_cpu(log->rst_info.r_page->sys_page_size);
	if (log->page_size != t32) {
		log->l_size = log->orig_file_size;
		log->page_size = norm_file_page(t32, &log->l_size,
						t32 == DefaultLogPageSize);
	}

If the on-disk page size is larger than the size used for the initial
allocation, log->page_size grows but one_page_buf is left at its
original, smaller size. A subsequent unaligned read_log_page() then
reads log->page_size bytes into the undersized scratch buffer:

	page_buf = page_off ? log->one_page_buf : *buffer;
	err = ntfs_read_run_nb_ra(ni->mi.sbi, &ni->file.run, page_vbo, page_buf,
				  log->page_size, NULL, &log->read_ahead);

overflowing the allocation. This is reachable when mounting a dirty
NTFS volume whose log was formatted with a page size larger than the
buffer initially allocated on the mounting host (for example a 64K-log
volume mounted on a host that allocated a 4K scratch buffer).

Grow one_page_buf when the adopted on-disk page size exceeds the size
used for the initial allocation. On krealloc() failure the original
buffer is left intact and freed by the existing error path.

## Which versions are affected by CVE-2026-72470?


## How do I fix CVE-2026-72470?

Apply the vendor's patch.

## Is CVE-2026-72470 being exploited?

There is no known exploitation of CVE-2026-72470 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72470 and fix it if it is affected.

What it is: CVE-2026-72470 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72470 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-72470/ (Markdown: https://insights.sbomify.com/CVE-2026-72470/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72470
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72470
- OSV: https://osv.dev/vulnerability/CVE-2026-72470

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72470/
Summaries are generated and may contain mistakes; the official description above is the record.