CVE-2019-16770

Name: CVE-2019-16770
Creator: NVD / NIST
Published: 2019-12-05T20:15:10.093+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.93%

Last modified Jun 17, 2026

CVE-2019-16770 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 1.93% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.93%

77.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Puma	Puma	>= 3.0.0, < 3.12.2
Puma	Puma	>= 4.0.0, < 4.3.1
Debian	Debian Linux	9.0

References

https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994Mitigation, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/05/msg00034.htmlMailing List, Third Party Advisory
https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994Mitigation, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/05/msg00034.htmlMailing List, Third Party Advisory

Timeline

Published: Dec 5, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-16770?

How severe is CVE-2019-16770?

CVE-2019-16770 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.93% probability of exploitation in the next 30 days.

How do I fix CVE-2019-16770?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-16770?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST