# CVE-2020-27221: Memory corruption in Eclipse OpenJ9

> A stack-based buffer overflow in Eclipse OpenJ9 during UTF-8 conversion allows attackers to execute arbitrary code or cause denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** 21 Jan 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-768g-gf3v-34vm

## What is CVE-2020-27221?

CVE-2020-27221 is a critical memory corruption vulnerability in The Eclipse Foundation Eclipse OpenJ9, published on 21 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse OpenJ9 up to and including version 0.23, there is potential for a stack-based buffer overflow when the virtual machine or JNI natives are converting from UTF-8 characters to platform encoding.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2020-27221?

It affects 1 product.


Products: Eclipse Openj9.

## How do I fix CVE-2020-27221?

Upgrade to a fixed version.

## Is CVE-2020-27221 being exploited?

There is no known exploitation of CVE-2020-27221 in the wild and no public exploit code.

## Other vulnerabilities in The Eclipse Foundation Eclipse OpenJ9

- [CVE-2021-41035](https://insights.sbomify.com/CVE-2021-41035/): Security feature bypass in Eclipse OMR (critical 9.8)
- [CVE-2019-11772](https://insights.sbomify.com/CVE-2019-11772/): Memory corruption in Eclipse OpenJ9 (critical 9.8)
- [CVE-2018-12547](https://insights.sbomify.com/CVE-2018-12547/): Memory corruption in Eclipse OpenJ9 (critical 9.8)
- [CVE-2018-12549](https://insights.sbomify.com/CVE-2018-12549/): Null dereference in Eclipse OpenJ9 (critical 9.8)
- [CVE-2018-12548](https://insights.sbomify.com/CVE-2018-12548/): Memory corruption in Eclipse OpenJ9 (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-27221 and fix it if it is affected.

What it is: CVE-2020-27221 is a critical memory corruption vulnerability in The Eclipse Foundation Eclipse OpenJ9, published on 21 Jan 2021. 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-2020-27221 in the wild and no public exploit code.

Affected product: The Eclipse Foundation Eclipse OpenJ9. 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-2020-27221/ (Markdown: https://insights.sbomify.com/CVE-2020-27221/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-27221
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-27221
- OSV: https://osv.dev/vulnerability/CVE-2020-27221

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-27221/
Summaries are generated and may contain mistakes; the official description above is the record.