# CVE-2020-9391: Memory corruption in n/a

> A flaw in the Linux kernel's brk system call on AArch64 ignores the top address byte, causing heap corruption and potential code execution.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Feb 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-9391, GHSA-gpf5-7vrh-q24p, UBUNTU-CVE-2020-9391

## What is CVE-2020-9391?

CVE-2020-9391 is a medium-severity memory corruption vulnerability in Fedoraproject Fedora, published on 25 Feb 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered in the Linux kernel 5.4 and 5.5 through 5.5.6 on the AArch64 architecture. It ignores the top byte in the address passed to the brk system call, potentially moving the memory break downwards when the application expects it to move upwards, aka CID-dcde237319e6. This has been observed to cause heap corruption with the GNU C Library malloc implementation.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2020-9391?

It affects 9 products.


Products: Fedoraproject Fedora, Linux kernel, Netapp Active Iq Unified Manager, Netapp Cloud Backup, Netapp Data Availability Services, Netapp H410c Firmware, Netapp Hci Management Node, Netapp Solidfire, Netapp Steelstore Cloud Integrated Storage.

## How do I fix CVE-2020-9391?

Apply the vendor's patch.

## Is CVE-2020-9391 being exploited?

There is no known exploitation of CVE-2020-9391 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-9391 and fix it if it is affected.

What it is: CVE-2020-9391 is a medium-severity memory corruption vulnerability in Fedoraproject Fedora, published on 25 Feb 2020. 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-2020-9391 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2020-9391/ (Markdown: https://insights.sbomify.com/CVE-2020-9391/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-9391
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-9391
- OSV: https://osv.dev/vulnerability/CVE-2020-9391

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-9391/
Summaries are generated and may contain mistakes; the official description above is the record.