{"cve":"CVE-2019-16770","nvd":{"published":"2019-12-05T20:15:10.093","modified":"2026-06-17T02:22:45.997","status":"Modified","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770"],"references":["https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994","https://lists.debian.org/debian-lts-announce/2022/05/msg00034.html","https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994","https://lists.debian.org/debian-lts-announce/2022/05/msg00034.html"],"products":["debian:debian_linux","puma:puma"],"source":"nvd","synced_at":"2026-10-19T20:59:27.069234358+00:00"},"epss":{"cve":"CVE-2019-16770","score":0.02014,"percentile":0.80898,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-7xx3-m584-x994","url":"https://osv.dev/vulnerability/GHSA-7xx3-m584-x994","summary":"A poorly-behaved client could use keepalive requests to monopolize Puma's reactor and create a denial of service attack","modified":"2026-07-08T06:00:11.133080946Z","packages":[{"ecosystem":"RubyGems","name":"puma","purl":"pkg:gem/puma","ranges":["<3.12.2"],"fixed":["3.12.2"]},{"ecosystem":"RubyGems","name":"puma","purl":"pkg:gem/puma","ranges":[">=4.0.0 <4.3.1"],"fixed":["4.3.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}