# CVE-2019-11778: Use after free in Eclipse Mosquitto

> A use-after-free vulnerability in Eclipse Mosquitto allows remote attackers to cause a denial of service via specific MQTT v5 client configurations.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Sep 2019
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-11778, GHSA-rr62-j9x2-468p

## What is CVE-2019-11778?

CVE-2019-11778 is a medium-severity use after free vulnerability in The Eclipse Foundation Eclipse Mosquitto, published on 18 Sep 2019. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

If an MQTT v5 client connects to Eclipse Mosquitto versions 1.6.0 to 1.6.4 inclusive, sets a last will and testament, sets a will delay interval, sets a session expiry interval, and the will delay interval is set longer than the session expiry interval, then a use after free error occurs, which has the potential to cause a crash in some situations.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2019-11778?

It affects 1 product.


Products: Eclipse Mosquitto.

## How do I fix CVE-2019-11778?

Upgrade to a fixed version.

## Is CVE-2019-11778 being exploited?

There is no known exploitation of CVE-2019-11778 in the wild and no public exploit code.

## Other vulnerabilities in The Eclipse Foundation Eclipse Mosquitto

- [CVE-2018-12550](https://insights.sbomify.com/CVE-2018-12550/): Auth bypass in Eclipse Mosquitto (high 8.1)
- [CVE-2018-12551](https://insights.sbomify.com/CVE-2018-12551/): Auth bypass in Eclipse Mosquitto (high 8.1)
- [CVE-2023-5632](https://insights.sbomify.com/CVE-2023-5632/): Unconditionally adding an event to the epoll causes excessive CPU consumption (high 7.5)
- [CVE-2023-28366](https://insights.sbomify.com/CVE-2023-28366/): Denial of service in n/a (high 7.5)
- [CVE-2021-41039](https://insights.sbomify.com/CVE-2021-41039/): Denial of service in Eclipse Mosquitto (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-11778 and fix it if it is affected.

What it is: CVE-2019-11778 is a medium-severity use after free vulnerability in The Eclipse Foundation Eclipse Mosquitto, published on 18 Sep 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-11778 in the wild and no public exploit code.

Affected product: The Eclipse Foundation Eclipse Mosquitto. 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-2019-11778/ (Markdown: https://insights.sbomify.com/CVE-2019-11778/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-11778
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-11778
- OSV: https://osv.dev/vulnerability/CVE-2019-11778

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-11778/
Summaries are generated and may contain mistakes; the official description above is the record.