CVE-2019-16770: Potential DOS attack in Puma
Vulnerability summary
CVE-2019-16770 is a high (CVSS 7.5) vulnerability in debian debian_linux. EPSS estimates a 2.01% chance of exploitation in the next 30 days, higher than 80.9% of scored vulnerabilities.
Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 21 · Related 20Timeline
- 05-12-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
6 scores · 5 sources · 2 versions- CVE.orgCNA5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LDiffers
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LDiffers
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · RubygemsEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LDiffers
EPSS trend
Probability
2.01%
Chance of exploitation in the next 30 days
Percentile
81%
Versus all other CVEs
30-day change
No change 0.00 pp
From 2.01% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian2 products
- puma< 3.12.0-4
- debian_linuxEOL9.0
Puma1 product
- puma≥ < 4.3.1, < 4.3.1 | ≥ 3.0.0, < 3.12.2 | ≥ 4.0.0, < 4.3.1
RubyGems1 product
- puma< 3.12.2 | ≥ 4.0.0, < 4.3.1
Ubuntu1 product
- puma< 3.12.0-4ubuntu1
4 vendors · 5 products
References
8 links- github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994X Refsource CONFIRMMitigationThird Party AdvisoryREPORTWEB
lists.debian.org/debian-lts-announce/2022/05/msg00034.htmlMailing ListX Refsource MLISTThird Party AdvisoryWEB