# CVE-2022-2928: An option refcount overflow exists in dhcpd

> An integer overflow in the DHCP server's option reference counting can cause the service to abort, leading to denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Oct 2022
- **Updated:** 17 Sep 2024
- **Also known as:** ALPINE-CVE-2022-2928, DEBIAN-CVE-2022-2928, GHSA-5fp7-mmwq-gvmw, UBUNTU-CVE-2022-2928

## What is CVE-2022-2928?

CVE-2022-2928 is a medium-severity vulnerability in Debian Debian Linux, published on 7 Oct 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In ISC DHCP 4.4.0 -> 4.4.3, ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16-P1, when the function option_code_hash_lookup() is called from add_option(), it increases the option's refcount field. However, there is not a corresponding call to option_dereference() to decrement the refcount field. The function add_option() is only used in server responses to lease query packets. Each lease query response calls this function for several options, so eventually, the reference counters could overflow and cause the server to abort.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-2928?

It affects 3 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Isc Dhcp.

## How do I fix CVE-2022-2928?

Apply the vendor's patch.

## Is CVE-2022-2928 being exploited?

There is no known exploitation of CVE-2022-2928 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-2928 and fix it if it is affected.

What it is: CVE-2022-2928 is a medium-severity vulnerability in Debian Debian Linux, published on 7 Oct 2022. 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-2022-2928 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-2022-2928/ (Markdown: https://insights.sbomify.com/CVE-2022-2928/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-2928
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-2928
- OSV: https://osv.dev/vulnerability/CVE-2022-2928

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-2928/
Summaries are generated and may contain mistakes; the official description above is the record.