# CVE-2018-4003: Memory corruption in CUJO

> An unauthenticated attacker can achieve arbitrary code execution on CUJO Smart Firewalls via a heap overflow in the mdnscap binary triggered by malicious mDNS messages.

- **Severity:** High 8.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Mar 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-v346-9qx9-79fj

## What is CVE-2018-4003?

CVE-2018-4003 is a high-severity memory corruption vulnerability in CUJO, published on 21 Mar 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An exploitable heap overflow vulnerability exists in the mdnscap binary of the CUJO Smart Firewall running firmware 7003. The string lengths are handled incorrectly when parsing character strings in mDNS resource records, leading to arbitrary code execution in the context of the mdnscap process. An unauthenticated attacker can send an mDNS message to trigger this vulnerability.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2018-4003?

It affects 1 product.


Products: Getcujo Smart Firewall.

## How do I fix CVE-2018-4003?

No fix has been published for CVE-2018-4003 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-4003 being exploited?

There is no known exploitation of CVE-2018-4003 in the wild and no public exploit code.

## Other vulnerabilities in CUJO

- [CVE-2018-4031](https://insights.sbomify.com/CVE-2018-4031/): Code injection in CUJO (critical 9.0)
- [CVE-2018-3963](https://insights.sbomify.com/CVE-2018-3963/): Command injection in CUJO (critical 9.0)
- [CVE-2018-3985](https://insights.sbomify.com/CVE-2018-3985/): Use after free in CUJO (high 8.3)
- [CVE-2018-3969](https://insights.sbomify.com/CVE-2018-3969/): Command injection in CUJO (high 8.2)
- [CVE-2018-4011](https://insights.sbomify.com/CVE-2018-4011/): Integer overflow in CUJO (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-4003 and fix it if it is affected.

What it is: CVE-2018-4003 is a high-severity memory corruption vulnerability in CUJO, published on 21 Mar 2019. 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-2018-4003 in the wild and no public exploit code.

Affected product: CUJO. 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-2018-4003/ (Markdown: https://insights.sbomify.com/CVE-2018-4003/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-4003
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-4003
- OSV: https://osv.dev/vulnerability/CVE-2018-4003

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-4003/
Summaries are generated and may contain mistakes; the official description above is the record.