# CVE-2021-46243: Null dereference in n/a

> An untrusted pointer dereference in HDF5 allows attackers to cause a Denial of Service via crafted files.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Jan 2022
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-46243, ECHO-106f-ca1d-e5c4, GHSA-2rqw-mg55-mp69, UBUNTU-CVE-2021-46243

## What is CVE-2021-46243?

CVE-2021-46243 is a medium-severity vulnerability in Hdfgroup Hdf5, published on 21 Jan 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

An untrusted pointer dereference vulnerability exists in HDF5 v1.13.1-1 via the function H5O__dtype_decode_helper () at hdf5/src/H5Odtype.c. This vulnerability can lead to a Denial of Service (DoS).

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-46243?

It affects 1 product.


Products: Hdfgroup Hdf5.

## How do I fix CVE-2021-46243?

Upgrade to a fixed version.

## Is CVE-2021-46243 being exploited?

There is no known exploitation of CVE-2021-46243 in the wild and no public exploit code.

## Other vulnerabilities in Hdfgroup Hdf5

- [CVE-2024-32608](https://insights.sbomify.com/CVE-2024-32608/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-29157](https://insights.sbomify.com/CVE-2024-29157/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-29159](https://insights.sbomify.com/CVE-2024-29159/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-29164](https://insights.sbomify.com/CVE-2024-29164/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-32611](https://insights.sbomify.com/CVE-2024-32611/): Other in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-46243 and fix it if it is affected.

What it is: CVE-2021-46243 is a medium-severity vulnerability in Hdfgroup Hdf5, published on 21 Jan 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-46243 in the wild and no public exploit code.

Affected product: Hdfgroup Hdf5. 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-2021-46243/ (Markdown: https://insights.sbomify.com/CVE-2021-46243/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46243
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46243
- OSV: https://osv.dev/vulnerability/CVE-2021-46243

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-46243/
Summaries are generated and may contain mistakes; the official description above is the record.