# CVE-2024-20303: Denial of service in Cisco IOS XE Software

> An unauthenticated adjacent attacker can cause a denial of service on Cisco IOS XE Wireless LAN Controllers by sending malicious mDNS packets.

- **Severity:** High 7.4 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/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:** No
- **Published:** 27 Mar 2024
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-jfv4-r4r3-xx7w

## What is CVE-2024-20303?

CVE-2024-20303 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 27 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the multicast DNS (mDNS) gateway feature of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition.

 This vulnerability is due to improper management of mDNS client entries. An attacker could exploit this vulnerability by connecting to the wireless network and sending a continuous stream of specific mDNS packets. A successful exploit could allow the attacker to cause the wireless controller to have high CPU utilization, which could lead to access points (APs) losing their connection to the controller and result in a DoS condition.

Weakness: CWE-459 (Incomplete Cleanup)

## Which versions are affected by CVE-2024-20303?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2024-20303?

No fix has been published for CVE-2024-20303 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-20303 being exploited?

There is no known exploitation of CVE-2024-20303 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios Xe

- [CVE-2023-20198](https://insights.sbomify.com/CVE-2023-20198/): Cisco IOS XE Web UI Privilege Escalation (critical 10.0, exploited in the wild)
- [CVE-2018-0151](https://insights.sbomify.com/CVE-2018-0151/): Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2023-20273](https://insights.sbomify.com/CVE-2023-20273/): Cisco IOS XE Web UI Command Injection (high 7.2, exploited in the wild)
- [CVE-2025-20188](https://insights.sbomify.com/CVE-2025-20188/): Hardcoded credentials in Cisco IOS XE Software (critical 10.0)
- [CVE-2021-34770](https://insights.sbomify.com/CVE-2021-34770/): Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-20303 and fix it if it is affected.

What it is: CVE-2024-20303 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 27 Mar 2024. 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-2024-20303 in the wild and no public exploit code.

Affected product: Cisco Ios Xe. 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-2024-20303/ (Markdown: https://insights.sbomify.com/CVE-2024-20303/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-20303
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-20303
- OSV: https://osv.dev/vulnerability/CVE-2024-20303

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-20303/
Summaries are generated and may contain mistakes; the official description above is the record.