# CVE-2021-20304: Integer overflow in OpenEXR

> An attacker can cause a denial of service by providing a crafted file that triggers an undefined right shift error in the OpenEXR library.

- **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:** 23 Aug 2022
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-20304, GHSA-m48r-2qrf-q5hh, OESA-2022-1867, OESA-2022-1868, UBUNTU-CVE-2021-20304

## What is CVE-2021-20304?

CVE-2021-20304 is a high-severity vulnerability in Openexr Openexr, published on 23 Aug 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in OpenEXR's hufDecode functionality. This flaw allows an attacker who can pass a crafted file to be processed by OpenEXR, to trigger an undefined right shift error. The highest threat from this vulnerability is to system availability.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2021-20304?

It affects 1 product.


Products: Openexr Openexr.

## How do I fix CVE-2021-20304?

Apply the vendor's patch.

## Is CVE-2021-20304 being exploited?

There is no known exploitation of CVE-2021-20304 in the wild and no public exploit code.

## Other vulnerabilities in Openexr Openexr

- [CVE-2023-5841](https://insights.sbomify.com/CVE-2023-5841/): OpenEXR Heap Overflow in Scanline Deep Data Parsing (critical 9.1)
- [CVE-2026-41142](https://insights.sbomify.com/CVE-2026-41142/): OpenEXR is Vulnerable to Integer overflow in ImageChannel::resize leads to heap OOB write via OpenEXRUtil public API (high 8.8)
- [CVE-2026-42216](https://insights.sbomify.com/CVE-2026-42216/): OpenEXR: Out-of-bounds read in `IDManifest::init()` during prefix expansion (high 8.8)
- [CVE-2017-9111](https://insights.sbomify.com/CVE-2017-9111/): OpenEXR invalid write (high 8.8)
- [CVE-2017-9113](https://insights.sbomify.com/CVE-2017-9113/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20304 and fix it if it is affected.

What it is: CVE-2021-20304 is a high-severity vulnerability in Openexr Openexr, published on 23 Aug 2022. 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-2021-20304 in the wild and no public exploit code.

Affected product: Openexr Openexr. 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-2021-20304/ (Markdown: https://insights.sbomify.com/CVE-2021-20304/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20304
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20304
- OSV: https://osv.dev/vulnerability/CVE-2021-20304

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20304/
Summaries are generated and may contain mistakes; the official description above is the record.