# CVE-2023-31130: Buffer Underwrite in ares_inet_net_pton()

> A buffer underflow in c-ares allows attackers to cause memory corruption and potential code execution if specific IPv6 addresses are configured.

- **Severity:** Medium 4.1 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 May 2023
- **Updated:** 13 Feb 2025
- **Also known as:** AZL-26914, AZL-26917, AZL-26922, AZL-26938, AZL-26940, AZL-26941, AZL-34781, AZL-43693, DEBIAN-CVE-2023-31130, ECHO-a21f-e650-029a, GHSA-x6mf-cxr9-8q6v, OESA-2023-1359, OESA-2023-1360, RHSA-2023:7392, UBUNTU-CVE-2023-31130

## What is CVE-2023-31130?

CVE-2023-31130 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 25 May 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

c-ares is an asynchronous resolver library. ares_inet_net_pton() is vulnerable to a buffer underflow for certain ipv6 addresses, in particular "0::00:00:00/2" was found to cause an issue.  C-ares only uses this function internally for configuration purposes which would require an administrator to configure such an address via ares_set_sortlist(). However, users may externally use ares_inet_net_pton() for other purposes and thus be vulnerable to more severe issues. This issue has been fixed in 1.19.1.

Weakness: CWE-787 (Out-of-bounds Write), CWE-124 (Buffer Underwrite)

## Which versions are affected by CVE-2023-31130?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `c-ares` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.2 |
| `c-ares-debuginfo` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.2 |
| `c-ares-debugsource` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.2 |
| `c-ares-devel` | Red Hat:rhel_eus:8.6::baseos | All versions | 0:1.13.0-6.el8_6.2 |

Products: C-Ares Project C-Ares, Debian Debian Linux, Fedoraproject Fedora.

## How do I fix CVE-2023-31130?

Upgrade to a fixed version.

## Is CVE-2023-31130 being exploited?

There is no known exploitation of CVE-2023-31130 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2022-4904](https://insights.sbomify.com/CVE-2022-4904/): Memory corruption in c-ares (high 8.6)
- [CVE-2023-32067](https://insights.sbomify.com/CVE-2023-32067/): 0-byte UDP payload DoS in c-ares (high 7.5)
- [CVE-2020-8277](https://insights.sbomify.com/CVE-2020-8277/): Uncontrolled Resource Consumption in node (high 7.5)
- [CVE-2023-31147](https://insights.sbomify.com/CVE-2023-31147/): Insufficient randomness in generation of DNS query IDs in c-ares (medium 5.9)
- [CVE-2021-3672](https://insights.sbomify.com/CVE-2021-3672/): Other in c-ares (medium 5.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-31130 and fix it if it is affected.

What it is: CVE-2023-31130 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 25 May 2023. 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-2023-31130 in the wild and no public exploit code.

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-2023-31130/ (Markdown: https://insights.sbomify.com/CVE-2023-31130/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-31130
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-31130
- OSV: https://osv.dev/vulnerability/CVE-2023-31130

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-31130/
Summaries are generated and may contain mistakes; the official description above is the record.