# CVE-2021-33285: Memory corruption in n/a

> A heap buffer overflow in NTFS-3G allows attackers to disclose memory or cause denial of service by mounting a crafted NTFS partition.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Sep 2021
- **Updated:** 3 Dec 2025
- **Also known as:** AZL-6748, DEBIAN-CVE-2021-33285, UBUNTU-CVE-2021-33285

## What is CVE-2021-33285?

CVE-2021-33285 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 7 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In NTFS-3G versions < 2021.8.22, when a specially crafted NTFS attribute is supplied to the function ntfs_get_attribute_value, a heap buffer overflow can occur allowing for memory disclosure or denial of service. The vulnerability is caused by an out-of-bound buffer access which can be triggered by mounting a crafted ntfs partition. The root cause is a missing consistency check after reading an MFT record : the "bytes_in_use" field should be less than the "bytes_allocated" field. When it is not, the parsing of the records proceeds into the wild.

Weakness: CWE-787 (Out-of-bounds Write), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2021-33285?

It affects 4 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Redhat Enterprise Linux, Tuxera Ntfs-3g.

## How do I fix CVE-2021-33285?

Upgrade to a fixed version.

## Is CVE-2021-33285 being exploited?

There is no known exploitation of CVE-2021-33285 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33285 and fix it if it is affected.

What it is: CVE-2021-33285 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 7 Sep 2021. 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-2021-33285 in the wild and no public exploit code.

Affected product: Debian Debian 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-2021-33285/ (Markdown: https://insights.sbomify.com/CVE-2021-33285/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33285
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33285
- OSV: https://osv.dev/vulnerability/CVE-2021-33285

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33285/
Summaries are generated and may contain mistakes; the official description above is the record.