# CVE-2018-12537: Moderate severity vulnerability that affects io.vertx:vertx-core

> Attackers can inject arbitrary headers into HTTP requests or responses by exploiting unfiltered carriage return and line feed characters in Vert.x.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Aug 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-6cw8-7j6c-hccp

## What is CVE-2018-12537?

CVE-2018-12537 is a medium-severity vulnerability in The Eclipse Foundation Eclipse Vert.x, published on 14 Aug 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse Vert.x version 3.0 to 3.5.1, the HttpServer response headers and HttpClient request headers do not filter carriage return and line feed characters from the header value. This allow unfiltered values to inject a new header in the client request or server response.

Weakness: CWE-20 (Improper Input Validation), CWE-93 (Improper Neutralization of CRLF Sequences)

## Which versions are affected by CVE-2018-12537?

2 open source packages ship an affected version, including io.vertx:vertx-core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `io.vertx:vertx-core` | Maven | From 3.0.0 | 3.5.2 |
| `io.vertx:vertx-core` | Maven | From 3.0.0 | 3.5.2 |

Products: Eclipse Vert.x.

## How do I fix CVE-2018-12537?

Upgrade io.vertx:vertx-core to 3.5.2 or later.

## Is CVE-2018-12537 being exploited?

There is no known exploitation of CVE-2018-12537 in the wild and no public exploit code.

Public exploit code:

- https://github.com/tafamace/CVE-2018-12537 (github_poc): https://github.com/tafamace/CVE-2018-12537

## Other vulnerabilities in The Eclipse Foundation Eclipse Vert.x

- [CVE-2019-17640](https://insights.sbomify.com/CVE-2019-17640/): Path Traversal in Eclipse Vert (critical 9.8)
- [CVE-2018-12542](https://insights.sbomify.com/CVE-2018-12542/): Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location (critical 9.8)
- [CVE-2018-12544](https://insights.sbomify.com/CVE-2018-12544/): Moderate severity vulnerability that affects io.vertx:vertx-core (critical 9.8)
- [CVE-2026-102469](https://insights.sbomify.com/CVE-2026-102469/): Deserialization in Eclipse Vert.x (critical 9.2)
- [CVE-2018-12540](https://insights.sbomify.com/CVE-2018-12540/): High severity vulnerability that affects io.vertx:vertx-web (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-12537 and fix it if it is affected.

What it is: CVE-2018-12537 is a medium-severity vulnerability in The Eclipse Foundation Eclipse Vert.x, published on 14 Aug 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-2018-12537 in the wild and no public exploit code.

Affected packages and fixed versions:
- io.vertx:vertx-core (Maven): affected from 3.0.0; fixed in 3.5.2
- io.vertx:vertx-core (Maven): affected from 3.0.0; fixed in 3.5.2

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-2018-12537/ (Markdown: https://insights.sbomify.com/CVE-2018-12537/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-12537
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-12537
- OSV: https://osv.dev/vulnerability/CVE-2018-12537

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-12537/
Summaries are generated and may contain mistakes; the official description above is the record.