# CVE-2026-72188: ntfs: sanitize MFT references returned from ntfs_lookup_inode_by_name()

> A crafted NTFS image can cause the Linux kernel to consume invalid error codes, potentially leading to system instability or denial of service.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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:** 17 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-72188, GHSA-mp9c-j9qx-8x7c, UBUNTU-CVE-2026-72188

## What is CVE-2026-72188?

CVE-2026-72188 is a critical 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: sanitize MFT references returned from ntfs_lookup_inode_by_name()

ntfs_lookup_inode_by_name() returns MFT references read from directory
index entries on disk. These values are untrusted, but the function can
currently return an error-marked MFT reference to its callers without
validating it.

Callers later decode lookup failures with MREF_ERR(). A crafted NTFS image
can set the MREF error bit while leaving the low bits as an arbitrary
value, causing callers to consume a bogus pseudo-errno instead of treating
the lookup result as corrupted on-disk metadata.

Fix this at the source by normalizing every error-marked MFT reference
returned from ntfs_lookup_inode_by_name() to ERR_MREF(-EIO). Apply this to
all four directory lookup return paths so every caller gets a validated
result without needing additional checks or an API change.

This keeps the sanitization in the common lookup helper, which is cleaner
than duplicating validation in each caller.

## Which versions are affected by CVE-2026-72188?


## How do I fix CVE-2026-72188?

Apply the vendor's patch.

## Is CVE-2026-72188 being exploited?

There is no known exploitation of CVE-2026-72188 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72188 and fix it if it is affected.

What it is: CVE-2026-72188 is a critical 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-2026-72188 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-2026-72188/ (Markdown: https://insights.sbomify.com/CVE-2026-72188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72188
- OSV: https://osv.dev/vulnerability/CVE-2026-72188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72188/
Summaries are generated and may contain mistakes; the official description above is the record.