# CVE-2018-19587: Null dereference in n/a

> A null pointer dereference in Cesanta Mongoose allows attackers to cause a denial of service via crafted MQTT packets.

- **Severity:** Medium 6.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 27 Nov 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-q23h-r653-rm5r

## What is CVE-2018-19587?

CVE-2018-19587 is a medium-severity vulnerability in Cesanta Mongoose, published on 27 Nov 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In Cesanta Mongoose 6.13, a SIGSEGV exists in the mongoose.c mg_mqtt_add_session() function.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2018-19587?

It affects 1 product.


Products: Cesanta Mongoose.

## How do I fix CVE-2018-19587?

No fix has been published for CVE-2018-19587 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-19587 being exploited?

There is no known exploitation of CVE-2018-19587 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-2018-19587 and fix it if it is affected.

What it is: CVE-2018-19587 is a medium-severity vulnerability in Cesanta Mongoose, published on 27 Nov 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-19587 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-2018-19587/ (Markdown: https://insights.sbomify.com/CVE-2018-19587/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-19587
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-19587
- OSV: https://osv.dev/vulnerability/CVE-2018-19587

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-19587/
Summaries are generated and may contain mistakes; the official description above is the record.