# CVE-2023-1981: Denial of service in avahi

> An unprivileged user can crash the Avahi daemon via a D-Bus call, causing a denial of service for network discovery services.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 26 May 2023
- **Updated:** 3 Nov 2025
- **Also known as:** ALPINE-CVE-2023-1981, ALSA-2023:7190, AZL-26789, AZL-34554, BELL-CVE-2023-1981, DEBIAN-CVE-2023-1981, DLA-3414-1, GHSA-55h6-xcvg-4r99, MGASA-2023-0158, OESA-2023-1240, RHSA-2023:7190, RLSA-2023:7190, SUSE-SU-2023:1956-1, SUSE-SU-2023:1993-1, SUSE-SU-2023:1994-1, UBUNTU-CVE-2023-1981, USN-6129-1, USN-6129-2, openSUSE-SU-2024:12854-1

## What is CVE-2023-1981?

CVE-2023-1981 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 26 May 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability was found in the avahi library. This flaw allows an unprivileged user to make a dbus call, causing the avahi daemon to crash.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-1981?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `avahi` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-autoipd` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-compat-howl` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-compat-howl-devel` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-compat-libdns_sd` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-compat-libdns_sd-devel` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-devel` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-glib` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-glib-devel` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-gobject` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-gobject-devel` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-libs` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-tools` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-ui` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-ui-devel` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-ui-gtk3` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `python3-avahi` | AlmaLinux:8 | All versions | 0.7-21.el8 |
| `avahi-autoipd-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-compat-howl-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-compat-libdns_sd-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-dnsconfd-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-glib-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-gobject-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-libs-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-tools` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-tools-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-ui-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-ui-gtk3` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi-ui-gtk3-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:0.7-21.el8 |
| `avahi` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-autoipd` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-autoipd-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-compat-howl-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-compat-libdns_sd-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-dnsconfd-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |
| `avahi-glib` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.7-21.el8 |

Products: Avahi Avahi, Fedoraproject Fedora, Redhat Enterprise Linux.

## How do I fix CVE-2023-1981?

Apply the vendor's patch.

## Is CVE-2023-1981 being exploited?

There is no known exploitation of CVE-2023-1981 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2017-6519](https://insights.sbomify.com/CVE-2017-6519/): Denial of service in n/a (critical 9.1)
- [CVE-2021-26720](https://insights.sbomify.com/CVE-2021-26720/): Path traversal in n/a (high 7.8)
- [CVE-2026-24401](https://insights.sbomify.com/CVE-2026-24401/): Avahi has Uncontrolled Recursion in lookup_handle_cname function (medium 6.5)
- [CVE-2025-68468](https://insights.sbomify.com/CVE-2025-68468/): Avahi has a reachable assertion in lookup_multicast_callback (medium 6.5)
- [CVE-2025-68471](https://insights.sbomify.com/CVE-2025-68471/): Avahi has a reachable assertion in lookup_start (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-1981 and fix it if it is affected.

What it is: CVE-2023-1981 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 26 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-2023-1981 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-2023-1981/ (Markdown: https://insights.sbomify.com/CVE-2023-1981/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-1981
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-1981
- OSV: https://osv.dev/vulnerability/CVE-2023-1981

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-1981/
Summaries are generated and may contain mistakes; the official description above is the record.