---
title: "CVE-2019-16770\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2019-16770?format=md
keywords: index, follow
---

# CVE-2019-16770

Publication date 5 December 2019

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2019-16770?format=md#impact-score)

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## Description

In Puma before versions 3.12.2 and 4.3.1, a poorly-behaved client could use
keepalive requests to monopolize Puma's reactor and create a denial of
service attack. If more keepalive connections to Puma are opened than there
are threads available, additional connections will wait permanently if the
attacker sends requests frequently enough. This vulnerability is patched in
Puma 4.3.1 and 3.12.2.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| puma | 20.04 LTS focal | Not affected |
| 19.10 eoan | Ignored end of life |
| 19.04 disco | Ignored end of life |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | None |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-16770)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-16770)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-16770)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2019-16770)

### Other references

* <https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994>
* <https://www.cve.org/CVERecord?id=CVE-2019-16770>