# CVE-2021-27419: uClibc-ng Integer Overflow or Wraparound

> An integer overflow in uClibc-ng's malloc-simple function allows attackers to cause crashes or execute arbitrary code via improper memory allocation.

- **Severity:** High 7.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 May 2022
- **Updated:** 16 Apr 2025
- **Also known as:** DEBIAN-CVE-2021-27419, GHSA-499x-cvfw-94w6

## What is CVE-2021-27419?

CVE-2021-27419 is a high-severity vulnerability in uClibc-ng, published on 3 May 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

uClibc-ng versions prior to 1.0.37 are vulnerable to integer wrap-around in functions malloc-simple. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2021-27419?

It affects 1 product.


Products: Uclibc-Ng Project Uclibc-Ng.

## How do I fix CVE-2021-27419?

Upgrade to a fixed version.

## Is CVE-2021-27419 being exploited?

There is no known exploitation of CVE-2021-27419 in the wild and no public exploit code.

## Other vulnerabilities in uClibc-ng

- [CVE-2021-43523](https://insights.sbomify.com/CVE-2021-43523/): Cross-site scripting in n/a (critical 9.6)
- [CVE-2016-2224](https://insights.sbomify.com/CVE-2016-2224/): Denial of service in n/a (high 7.5)
- [CVE-2016-2225](https://insights.sbomify.com/CVE-2016-2225/): Denial of service in n/a (high 7.5)
- [CVE-2016-6264](https://insights.sbomify.com/CVE-2016-6264/): Integer overflow in n/a (high 7.5)
- [CVE-2022-30295](https://insights.sbomify.com/CVE-2022-30295/): Other in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27419 and fix it if it is affected.

What it is: CVE-2021-27419 is a high-severity vulnerability in uClibc-ng, published on 3 May 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-2021-27419 in the wild and no public exploit code.

Affected product: uClibc-ng. 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-2021-27419/ (Markdown: https://insights.sbomify.com/CVE-2021-27419/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27419
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27419
- OSV: https://osv.dev/vulnerability/CVE-2021-27419

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27419/
Summaries are generated and may contain mistakes; the official description above is the record.