# CVE-2019-17513: io.ratpack:ratpack-core vulnerable to Improper Neutralization of Special Elements in Output ('Injection')

> Attackers can perform HTTP Response Splitting by injecting control characters into headers constructed from untrusted data in the Ratpack framework.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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:** 18 Oct 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-mvqp-q37c-wf9j

## What is CVE-2019-17513?

CVE-2019-17513 is a high-severity vulnerability in n/a, published on 18 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Ratpack before 1.7.5. Due to a misuse of the Netty library class DefaultHttpHeaders, there is no validation that headers lack HTTP control characters. Thus, if untrusted data is used to construct HTTP headers with Ratpack, HTTP Response Splitting can occur.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2019-17513?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `io.ratpack:ratpack-core` | Maven | All versions | 1.7.5 |
| `io.ratpack:ratpack-core` | Maven | All versions | 1.7.5 |

Products: Ratpack Project Ratpack.

## How do I fix CVE-2019-17513?

Upgrade io.ratpack:ratpack-core to 1.7.5 or later.

## Is CVE-2019-17513 being exploited?

There is no known exploitation of CVE-2019-17513 in the wild and no public exploit code.

Public exploit code:

- ratpack with CVE-2019-17513 (github_poc): https://github.com/epicosy/Ratpack-1

## Other vulnerabilities in n/a

- [CVE-2021-29485](https://insights.sbomify.com/CVE-2021-29485/): Remote Code Execution Vulnerability in Session Storage (critical 9.9)
- [CVE-2021-29479](https://insights.sbomify.com/CVE-2021-29479/): Cached redirect poisoning via X-Forwarded-Host header (high 7.0)
- [CVE-2021-29481](https://insights.sbomify.com/CVE-2021-29481/): Client side sessions should not allow unencrypted storage (medium 6.5)
- [CVE-2021-29480](https://insights.sbomify.com/CVE-2021-29480/): Default client side session signing key is highly predictable (medium 4.4)
- [CVE-2019-11808](https://insights.sbomify.com/CVE-2019-11808/): Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in Ratpack (low 3.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-17513 and fix it if it is affected.

What it is: CVE-2019-17513 is a high-severity vulnerability in n/a, published on 18 Oct 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-2019-17513 in the wild and no public exploit code.

Affected packages and fixed versions:
- io.ratpack:ratpack-core (Maven): affected all versions; fixed in 1.7.5
- io.ratpack:ratpack-core (Maven): affected all versions; fixed in 1.7.5

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-2019-17513/ (Markdown: https://insights.sbomify.com/CVE-2019-17513/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-17513
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-17513
- OSV: https://osv.dev/vulnerability/CVE-2019-17513

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-17513/
Summaries are generated and may contain mistakes; the official description above is the record.