# CVE-2017-7651: Denial of service in Eclipse Mosquitto

> Unauthenticated attackers can crash the Eclipse Mosquitto MQTT server by exhausting RAM with numerous large-payload connections during the handshake phase.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2018
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2017-7651, DEBIAN-CVE-2017-7651, GHSA-5jfw-q283-hm73, UBUNTU-CVE-2017-7651

## What is CVE-2017-7651?

CVE-2017-7651 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 24 Apr 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse Mosquitto 1.4.14, a user can shutdown the Mosquitto server simply by filling the RAM memory with a lot of connections with large payload. This can be done without authentications if occur in connection phase of MQTT protocol.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-789 (Memory Allocation with Excessive Size Value)

## Which versions are affected by CVE-2017-7651?

It affects 2 products.


Products: Debian Debian Linux, Eclipse Mosquitto.

## How do I fix CVE-2017-7651?

Upgrade to a fixed version.

## Is CVE-2017-7651 being exploited?

There is no known exploitation of CVE-2017-7651 in the wild and no public exploit code.

Public exploit code:

- This is the repository used for CVE-2017-7651 for exploiting mosquitto 1.4.14 (github_poc): https://github.com/St3v3nsS/CVE-2017-7651
- PoC for CVE-2017-7651 (github_poc): https://github.com/mukkul007/MqttAttack

## 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-2017-7651 and fix it if it is affected.

What it is: CVE-2017-7651 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 24 Apr 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-7651 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-2017-7651/ (Markdown: https://insights.sbomify.com/CVE-2017-7651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7651
- OSV: https://osv.dev/vulnerability/CVE-2017-7651

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-7651/
Summaries are generated and may contain mistakes; the official description above is the record.