{"cve":"CVE-2024-21647","nvd":{"published":"2024-01-08T14:15:47.640","modified":"2026-06-17T07:09:55.307","status":"Modified","description":"Puma is a web server for Ruby/Rack applications built for parallelism. Prior to version 6.4.2, puma exhibited incorrect behavior when parsing chunked transfer encoding bodies in a way that allowed HTTP request smuggling. Fixed versions limits the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption. This vulnerability has been fixed in versions 6.4.2 and 5.6.8.","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-444"],"references":["https://github.com/puma/puma/commit/5fc43d73b6ff193325e657a24ed76dec79133e93","https://github.com/puma/puma/security/advisories/GHSA-c2f4-cvqm-65w2","https://github.com/puma/puma/commit/5fc43d73b6ff193325e657a24ed76dec79133e93","https://github.com/puma/puma/security/advisories/GHSA-c2f4-cvqm-65w2","https://lists.debian.org/debian-lts-announce/2024/11/msg00004.html"],"products":["puma:puma"],"source":"nvd","synced_at":"2026-10-19T21:43:38.875533635+00:00"},"epss":{"cve":"CVE-2024-21647","score":0.00958,"percentile":0.61501,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-c2f4-cvqm-65w2","url":"https://osv.dev/vulnerability/GHSA-c2f4-cvqm-65w2","summary":"Puma HTTP Request/Response Smuggling vulnerability","modified":"2026-09-10T03:49:24.667590732Z","packages":[{"ecosystem":"RubyGems","name":"puma","purl":"pkg:gem/puma","ranges":[">=6.0.0 <6.4.2"],"fixed":["6.4.2"]},{"ecosystem":"RubyGems","name":"puma","purl":"pkg:gem/puma","ranges":["<5.6.8"],"fixed":["5.6.8"]}]}],"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."]}