{"cve":"CVE-2025-6442","nvd":{"published":"2025-06-25T17:15:40.117","modified":"2026-06-17T10:01:54.183","status":"Analyzed","description":"Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.\n\nThe specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","score":5.9},"cwes":["CWE-444"],"references":["https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864","https://www.zerodayinitiative.com/advisories/ZDI-25-414/"],"products":["ruby-lang:webrick"],"source":"nvd","synced_at":"2026-10-19T22:03:23.287444849+00:00"},"epss":{"cve":"CVE-2025-6442","score":0.00495,"percentile":0.42474,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-r995-q44h-hr64","url":"https://osv.dev/vulnerability/GHSA-r995-q44h-hr64","summary":"Ruby WEBrick read_headers method can lead to HTTP Request/Response Smuggling","modified":"2025-06-30T13:26:07.070970Z","packages":[{"ecosystem":"RubyGems","name":"webrick","purl":"pkg:gem/webrick","ranges":["<1.8.2"],"fixed":["1.8.2"]}]}],"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."]}