# CVE-2021-39536: Memory corruption in n/a

> A heap-based buffer overflow in the libxsmm JIT code allows attackers to execute arbitrary code or cause denial of service.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 Sep 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-39536, GHSA-h9fc-rg7x-48xg

## What is CVE-2021-39536?

CVE-2021-39536 is a high-severity memory corruption vulnerability in n/a, published on 20 Sep 2021. 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 issue was discovered in libxsmm through v1.16.1-93. The JIT code has a heap-based buffer overflow.

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

## Which versions are affected by CVE-2021-39536?

It affects 1 product.


Products: Libxsmm Project Libxsmm.

## How do I fix CVE-2021-39536?

Upgrade to a fixed version.

## Is CVE-2021-39536 being exploited?

There is no known exploitation of CVE-2021-39536 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2018-20541](https://insights.sbomify.com/CVE-2018-20541/): Memory corruption in n/a (high 8.8)
- [CVE-2018-20542](https://insights.sbomify.com/CVE-2018-20542/): Memory corruption in n/a (high 8.8)
- [CVE-2021-39535](https://insights.sbomify.com/CVE-2021-39535/): Null dereference in n/a (medium 6.5)
- [CVE-2018-20543](https://insights.sbomify.com/CVE-2018-20543/): Denial of service in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-39536 and fix it if it is affected.

What it is: CVE-2021-39536 is a high-severity memory corruption vulnerability in n/a, published on 20 Sep 2021. 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-2021-39536 in the wild and no public exploit code.

Affected product: n/a. 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-2021-39536/ (Markdown: https://insights.sbomify.com/CVE-2021-39536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-39536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-39536
- OSV: https://osv.dev/vulnerability/CVE-2021-39536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-39536/
Summaries are generated and may contain mistakes; the official description above is the record.