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CVE-2019-16770

26
FAUCET Score

CVE-2019-16770 describes a Denial of Service (DoS) vulnerability in Puma web server versions prior to 3.12.2 and 4.3.1, affecting Debian and Puma products. A remote, unauthenticated attacker can exploit this by monopolizing Puma's reactor with excessive keepalive requests, causing new connections to permanently wait. Rated High severity (CVSS 7.5), this vulnerability has a low attack complexity and can lead to a complete loss of availability. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.0.0, < 3.12.2CPE matchmatch criteria
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*
>= 4.0.0, < 4.3.1CPE matchmatch criteria
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
LOW
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.96%
Probability of exploitation in next 30 days
EPSS Percentile
78.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0196 is in the 62nd percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

rubygemspatch availablevia ghsa
Product: pumaFixed in: 3.12.2
rubygemspatch availablevia ghsa
Product: pumaFixed in: 4.3.1
github_advisoryworkaround availablevia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: CloudForms Management Engine 5Fixed in: rubygem-puma
redhatend of lifevia redhat_api
Product: Red Hat Software CollectionsFixed in: rh-ror50-rubygem-puma
redhatend of lifevia redhat_api
Product: Red Hat Storage 3Fixed in: rubygem-puma

Vendor Advisories (2)

rubygemsGHSA-7xx3-m584-x994medium

A poorly-behaved client could use keepalive requests to monopolize Puma's reactor and create a denial of service attack

Dec 5, 2019
redhatCVE-2019-16770Moderate

rubygem-puma: keepalive requests from poorly-behaved client leads to denial of service

Dec 5, 2019

References

github.com / puma/puma/security/advisories/GHSA-7xx3-m584-x994
MitigationThird Party Advisory
lists.debian.org / debian-lts-announce/2022/05/msg00034.html
Mailing ListThird Party Advisory