# CVE-2018-20433: XML External Entity Reference in mchange:c3p0

> An attacker can exploit an XML External Entity vulnerability in c3p0 during initialization to read sensitive files or cause denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 Dec 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-20433, DLA-1621-1, GHSA-q485-j897-qc27, UBUNTU-CVE-2018-20433, openSUSE-SU-2024:10669-1

## What is CVE-2018-20433?

CVE-2018-20433 is a critical vulnerability in Debian Debian Linux, published on 24 Dec 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

c3p0 0.9.5.2 allows XXE in extractXmlConfigFromInputStream in com/mchange/v2/c3p0/cfg/C3P0ConfigXmlUtils.java during initialization.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2018-20433?

2 open source packages ship an affected version, including com.mchange:c3p0. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `com.mchange:c3p0` | Maven | All versions | 0.9.5.3 |
| `com.mchange:c3p0` | Maven | All versions | 0.9.5.3 |
| `c3p0` | openSUSE:Tumbleweed | All versions | 0.9.5.5-1.3 |

Products: Debian Debian Linux, Mchange C3p0.

## How do I fix CVE-2018-20433?

Upgrade com.mchange:c3p0 to 0.9.5.3 or later.

## Is CVE-2018-20433 being exploited?

There is no known exploitation of CVE-2018-20433 in the wild and no public exploit code.

Public exploit code:

- version between CVE-2018-20433 and CVE-2019-5427 (github_poc): https://github.com/shanika04/cp30_XXE_partial_fix

## 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-2018-20433 and fix it if it is affected.

What it is: CVE-2018-20433 is a critical vulnerability in Debian Debian Linux, published on 24 Dec 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-2018-20433 in the wild and no public exploit code.

Affected packages and fixed versions:
- com.mchange:c3p0 (Maven): affected all versions; fixed in 0.9.5.3
- com.mchange:c3p0 (Maven): affected all versions; fixed in 0.9.5.3

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-2018-20433/ (Markdown: https://insights.sbomify.com/CVE-2018-20433/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20433
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20433
- OSV: https://osv.dev/vulnerability/CVE-2018-20433

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20433/
Summaries are generated and may contain mistakes; the official description above is the record.