# CVE-2019-16792: HTTP Request Smuggling: Content-Length Sent Twice in Waitress

> Attackers can smuggle HTTP requests by sending duplicate Content-Length headers, bypassing security controls and potentially accessing sensitive data.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Jan 2020
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-16792, GHSA-4ppp-gpcr-7qf6, GHSA-j7j6-7hfx-5522, PYSEC-2020-178, UBUNTU-CVE-2019-16792

## What is CVE-2019-16792?

CVE-2019-16792 is a high-severity vulnerability in Debian Debian Linux, published on 22 Jan 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.

Weakness: CWE-444 (Inconsistent Interpretation of HTTP Requests)

## Which versions are affected by CVE-2019-16792?

5 open source packages ship an affected version, including waitress. It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `waitress` | PyPI | All versions | 1.4.0 |
| `waitress` | PyPI | All versions | 1.4.0 |
| `waitress` | PyPI | All versions | 1.4.0 |
| `waitress` | PyPI | All versions | 1.4.0 |
| `waitress` | PyPI | All versions | 1.4.0 |

Products: Agendaless Waitress, Debian Debian Linux, Oracle Communications Cloud Native Core Network Function Cloud Native Environment.

## How do I fix CVE-2019-16792?

Upgrade waitress to 1.4.0 or later.

## Is CVE-2019-16792 being exploited?

There is no known exploitation of CVE-2019-16792 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2024-49768](https://insights.sbomify.com/CVE-2024-49768/): Waitress has request processing race condition in HTTP pipelining with invalid first request (critical 9.1)
- [CVE-2024-49769](https://insights.sbomify.com/CVE-2024-49769/): Waitress has a denial of service leading to high CPU usage/resource exhaustion (high 7.5)
- [CVE-2022-24761](https://insights.sbomify.com/CVE-2022-24761/): HTTP Request Smuggling in waitress (high 7.5)
- [CVE-2019-16789](https://insights.sbomify.com/CVE-2019-16789/): HTTP Request Smuggling in Waitress: Invalid whitespace characters in headers (high 7.1)
- [CVE-2019-16785](https://insights.sbomify.com/CVE-2019-16785/): HTTP Request Smuggling: LF vs CRLF handling in Waitress (high 7.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-16792 and fix it if it is affected.

What it is: CVE-2019-16792 is a high-severity vulnerability in Debian Debian Linux, published on 22 Jan 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-16792 in the wild and no public exploit code.

Affected packages and fixed versions:
- waitress (PyPI): affected all versions; fixed in 1.4.0
- waitress (PyPI): affected all versions; fixed in 1.4.0
- waitress (PyPI): affected all versions; fixed in 1.4.0
- waitress (PyPI): affected all versions; fixed in 1.4.0
- waitress (PyPI): affected all versions; fixed in 1.4.0

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-2019-16792/ (Markdown: https://insights.sbomify.com/CVE-2019-16792/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-16792
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-16792
- OSV: https://osv.dev/vulnerability/CVE-2019-16792

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-16792/
Summaries are generated and may contain mistakes; the official description above is the record.