# CVE-2026-72202: ntfs: avoid heap allocation for free-cluster readahead state

> A memory allocation failure in the Linux kernel NTFS driver can cause indefinite blocking of processes waiting for free cluster counts, leading to denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-72202, GHSA-r757-m3xv-cw84, UBUNTU-CVE-2026-72202

## What is CVE-2026-72202?

CVE-2026-72202 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

ntfs: avoid heap allocation for free-cluster readahead state

get_nr_free_clusters() allocates a temporary file_ra_state before it
publishes the precomputed free cluster count, sets NVolFreeClusterKnown(),
and wakes vol->free_waitq. If that allocation fails, the worker returns
without setting the flag or waking waiters, so callers waiting for the free
count can block indefinitely.

The readahead state is only used synchronously while scanning the bitmap.
Keep it on the stack and pass it by address to the readahead helper. This
eliminates the early allocation failure path instead of adding a special
case that publishes a conservative count and wakes the waitqueue.
Zero-initialize the on-stack state because file_ra_state_init() only sets
ra_pages and prev_pos.

Apply the same treatment to __get_nr_free_mft_records(), which scans the
MFT bitmap with the same short-lived readahead state.

## Which versions are affected by CVE-2026-72202?


## How do I fix CVE-2026-72202?

Apply the vendor's patch.

## Is CVE-2026-72202 being exploited?

There is no known exploitation of CVE-2026-72202 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72202 and fix it if it is affected.

What it is: CVE-2026-72202 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72202 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-2026-72202/ (Markdown: https://insights.sbomify.com/CVE-2026-72202/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72202
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72202
- OSV: https://osv.dev/vulnerability/CVE-2026-72202

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72202/
Summaries are generated and may contain mistakes; the official description above is the record.