# CVE-2018-18765: Information disclosure in n/a

> A heap-based buffer over-read in Cesanta Mongoose allows attackers to disclose memory or cause denial of service via crafted MQTT packets.

- **Severity:** Critical 9.1 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** 28 Oct 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-18765, GHSA-w62j-xhgm-2ggr

## What is CVE-2018-18765?

CVE-2018-18765 is a critical vulnerability in Cesanta Mongoose, published on 28 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An exploitable arbitrary memory read vulnerability exists in the MQTT packet-parsing functionality of Cesanta Mongoose 6.13. It is a heap-based buffer over-read in mg_mqtt_next_subscribe_topic. A specially crafted MQTT SUBSCRIBE packet can cause an arbitrary out-of-bounds memory read potentially resulting in information disclosure and denial of service. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2018-18765?

It affects 1 product.


Products: Cesanta Mongoose.

## How do I fix CVE-2018-18765?

Upgrade to a fixed version.

## Is CVE-2018-18765 being exploited?

There is no known exploitation of CVE-2018-18765 in the wild and no public exploit code.

## Other vulnerabilities in Cesanta Mongoose

- [CVE-2022-25299](https://insights.sbomify.com/CVE-2022-25299/): Arbitrary File Write (critical 9.8)
- [CVE-2020-25756](https://insights.sbomify.com/CVE-2020-25756/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-19307](https://insights.sbomify.com/CVE-2019-19307/): Integer overflow in n/a (critical 9.8)
- [CVE-2019-12951](https://insights.sbomify.com/CVE-2019-12951/): Memory corruption in n/a (critical 9.8)
- [CVE-2018-20353](https://insights.sbomify.com/CVE-2018-20353/): Use after free in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-18765 and fix it if it is affected.

What it is: CVE-2018-18765 is a critical vulnerability in Cesanta Mongoose, published on 28 Oct 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-2018-18765 in the wild and no public exploit code.

Affected product: Cesanta Mongoose. 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-2018-18765/ (Markdown: https://insights.sbomify.com/CVE-2018-18765/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-18765
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-18765
- OSV: https://osv.dev/vulnerability/CVE-2018-18765

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-18765/
Summaries are generated and may contain mistakes; the official description above is the record.