# CVE-2020-14354: Use after free in c-ares

> An attacker can crash services using c-ares by triggering a use-after-free condition during asynchronous DNS resolution cleanup.

- **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L`)
- **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:** 13 May 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-14354, GHSA-xxmg-3gv9-85h2

## What is CVE-2020-14354?

CVE-2020-14354 is a low-severity use after free vulnerability in Fedoraproject Fedora, published on 13 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A possible use-after-free and double-free in c-ares lib version 1.16.0 if ares_destroy() is called prior to ares_getaddrinfo() completing. This flaw possibly allows an attacker to crash the service that uses c-ares lib. The highest threat from this vulnerability is to this service availability.

Weakness: CWE-416 (Use After Free), CWE-415 (Double Free), CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-14354?

It affects 2 products.


Products: C-Ares C-Ares, Fedoraproject Fedora.

## How do I fix CVE-2020-14354?

Upgrade to a fixed version.

## Is CVE-2020-14354 being exploited?

There is no known exploitation of CVE-2020-14354 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2016-5180](https://insights.sbomify.com/CVE-2016-5180/): Memory corruption in n/a (critical 9.8)
- [CVE-2017-1000381](https://insights.sbomify.com/CVE-2017-1000381/): Information disclosure in n/a (high 7.5)
- [CVE-2025-62408](https://insights.sbomify.com/CVE-2025-62408/): c-ares has a Use After Free vulnerability when connection is cleaned up after error (medium 5.9)
- [CVE-2020-22217](https://insights.sbomify.com/CVE-2020-22217/): Memory corruption in n/a (medium 5.9)
- [CVE-2024-25629](https://insights.sbomify.com/CVE-2024-25629/): c-ares out of bounds read in ares__read_line() (medium 4.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-14354 and fix it if it is affected.

What it is: CVE-2020-14354 is a low-severity use after free vulnerability in Fedoraproject Fedora, published on 13 May 2021. 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-2020-14354 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-2020-14354/ (Markdown: https://insights.sbomify.com/CVE-2020-14354/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-14354
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-14354
- OSV: https://osv.dev/vulnerability/CVE-2020-14354

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-14354/
Summaries are generated and may contain mistakes; the official description above is the record.