# CVE-2020-22217: Memory corruption in n/a

> A buffer overflow in the c-ares DNS library allows attackers to execute arbitrary code or cause denial of service via crafted SOA replies.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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:** 22 Aug 2023
- **Updated:** 3 Oct 2024
- **Also known as:** AZL-28597, DEBIAN-CVE-2020-22217, DLA-3567-1, GHSA-88q4-8vpj-fqpg, RHSA-2024:0419, RHSA-2024:0578, SUSE-SU-2023:3690-1, UBUNTU-CVE-2020-22217, USN-6376-1

## What is CVE-2020-22217?

CVE-2020-22217 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 22 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Buffer overflow vulnerability in c-ares before 1_16_1 thru 1_17_0 via function ares_parse_soa_reply in ares_parse_soa_reply.c.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2020-22217?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `c-ares` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.3 |
| `c-ares-debuginfo` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.3 |
| `c-ares-debugsource` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.3 |
| `c-ares-devel` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.3 |
| `c-ares` | Red Hat:rhel_eus:8.8::baseos | All versions | 0:1.13.0-6.el8_8.4 |
| `c-ares-debuginfo` | Red Hat:rhel_eus:8.8::baseos | All versions | 0:1.13.0-6.el8_8.4 |
| `c-ares-debugsource` | Red Hat:rhel_eus:8.8::baseos | All versions | 0:1.13.0-6.el8_8.4 |
| `c-ares-devel` | Red Hat:rhel_eus:8.8::baseos | All versions | 0:1.13.0-6.el8_8.4 |
| `libcares2` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 1.9.1-9.18.1 |
| `libcares2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 1.9.1-9.18.1 |
| `libcares2` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 1.9.1-9.18.1 |
| `libcares2` | SUSE:Linux Enterprise Workstation Extension 12 SP5 | All versions | 1.9.1-9.18.1 |

Products: C-Ares C-Ares, Debian Debian Linux.

## How do I fix CVE-2020-22217?

Upgrade to a fixed version.

## Is CVE-2020-22217 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-22217 exists.

## Other vulnerabilities in Debian Debian Linux

- [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-2024-25629](https://insights.sbomify.com/CVE-2024-25629/): c-ares out of bounds read in ares__read_line() (medium 4.4)
- [CVE-2020-14354](https://insights.sbomify.com/CVE-2020-14354/): Use after free in c-ares (low 3.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-22217 and fix it if it is affected.

What it is: CVE-2020-22217 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 22 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-22217 exists.

Affected product: Debian Debian Linux. 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-2020-22217/ (Markdown: https://insights.sbomify.com/CVE-2020-22217/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-22217
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-22217
- OSV: https://osv.dev/vulnerability/CVE-2020-22217

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-22217/
Summaries are generated and may contain mistakes; the official description above is the record.