{"cve":"CVE-2020-25613","nvd":{"published":"2020-10-06T13:15:13.823","modified":"2026-06-17T03:06:58.977","status":"Modified","description":"An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.","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:H/A:N","score":7.5},"cwes":["CWE-444"],"references":["https://github.com/ruby/webrick/commit/8946bb38b4d87549f0d99ed73c62c41933f97cc7","https://hackerone.com/reports/965267","https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PFP3E7KXXT3H3KA6CBZPUOGA5VPFARRJ/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YTZURYROG3FFED3TYCQOBV66BS4K6WOV/"],"products":["fedoraproject:fedora","ruby-lang:ruby","ruby-lang:webrick"],"source":"nvd","synced_at":"2026-10-19T21:09:53.489947993+00:00"},"epss":{"cve":"CVE-2020-25613","score":0.03818,"percentile":0.90059,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-gwfg-cqmg-cf8f","url":"https://osv.dev/vulnerability/GHSA-gwfg-cqmg-cf8f","summary":"WEBRick vulnerable to HTTP Request/Response Smuggling","modified":"2025-05-29T23:24:50.525424Z","packages":[{"ecosystem":"RubyGems","name":"webrick","purl":"pkg:gem/webrick","ranges":[">=1.6.0 <1.6.1"],"fixed":["1.6.1"]},{"ecosystem":"RubyGems","name":"webrick","purl":"pkg:gem/webrick","ranges":[">=1.5.0 <1.5.1"],"fixed":["1.5.1"]},{"ecosystem":"RubyGems","name":"webrick","purl":"pkg:gem/webrick","ranges":["<1.4.4"],"fixed":["1.4.4"]}]}],"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."]}