{"schemaVersion":3,"id":"CVE-2025-6442","aliases":["UBUNTU-CVE-2025-6442","USN-7709-1","DEBIAN-CVE-2025-6442","GHSA-r995-q44h-hr64"],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2025-06-25T16:52:24.625Z","modified":"2025-06-25T20:42:41.093Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.5,"severity":"medium","version":"3.0","versionLabel":"v3.0","source":"CVE.org","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.0","versionLabel":"v3.0","source":"CVE.org","score":6.5,"severity":"medium","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":5.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","exploitability":5.6,"impact":6,"computed":true},{"version":"3.0","versionLabel":"v3.0","source":"OSV · Ubuntu","score":6.5,"severity":"medium","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","exploitability":5.6,"impact":7,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":5.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","exploitability":5.6,"impact":6,"computed":true},{"version":"3.0","versionLabel":"v3.0","source":"OSV · Rubygems","score":6.5,"severity":"medium","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","exploitability":5.6,"impact":7,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":5.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","exploitability":null,"impact":null,"computed":false},{"version":"3.0","versionLabel":"v3.0","source":"NVD","score":6.5,"severity":"medium","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00495,"percentile":0.41182,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0.022000000000000058,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.00473},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00442,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00495,"percentile":0.41182}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00473,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00495,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00495,"percentile":0.41182}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-444","name":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","description":"The product acts as an intermediary HTTP agent\n         (such as a proxy or firewall) in the data flow between two\n         entities such as a client and server, but it does not\n         interpret malformed HTTP requests or responses in ways that\n         are consistent with how the messages will be processed by\n         those entities that are at the ultimate destination.","type":"weakness","status":"Incomplete","abstraction":"Base","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/444.html"}],"affected":[{"vendor":"debian","product":"ruby-webrick","name":"ruby-webrick","label":"ruby-webrick","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/ruby-webrick","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 1.9.1-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 1.9.1-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"jruby","name":"jruby","label":"jruby","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/jruby","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"ruby-webrick","name":"ruby-webrick","label":"ruby-webrick","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/ruby-webrick","purlType":"deb","versions":[{"text":"< 1.9.1-1","noFixRecorded":false,"fixedIn":null},{"text":"< 1.7.0-3ubuntu0.2","noFixRecorded":false,"fixedIn":null},{"text":"< 1.8.1-1ubuntu0.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.9.1-1 | < 1.7.0-3ubuntu0.2 | < 1.8.1-1ubuntu0.2","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"ruby2.3","name":"ruby2.3","label":"ruby2.3","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/ruby2.3","purlType":"deb","versions":[{"text":"< 2.3.1-2~ubuntu16.04.16+esm11","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.3.1-2~ubuntu16.04.16+esm11","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"ruby2.5","name":"ruby2.5","label":"ruby2.5","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/ruby2.5","purlType":"deb","versions":[{"text":"< 2.5.1-1ubuntu1.16+esm6","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.5.1-1ubuntu1.16+esm6","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"ruby2.7","name":"ruby2.7","label":"ruby2.7","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/ruby2.7","purlType":"deb","versions":[{"text":"< 2.7.0-5ubuntu1.18+esm3","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.7.0-5ubuntu1.18+esm3","eol":null,"hubHref":null},{"vendor":"RubyGems","product":"webrick","name":"webrick","label":"webrick","ecosystem":"RubyGems","cpePart":null,"purl":"pkg:gem/webrick","purlType":"gem","versions":[{"text":"< 1.8.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.8.2","eol":null,"hubHref":null},{"vendor":"ruby-lang","product":"webrick","name":"webrick","label":"webrick","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.8.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.8.2","eol":null,"hubHref":"/vendor/ruby-lang/webrick"},{"vendor":"ruby","product":"webrick","name":"WEBrick","label":"webrick","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"1.8.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"1.8.1","eol":null,"hubHref":"/vendor/ruby/webrick"}],"affectedCount":9,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://www.zerodayinitiative.com/advisories/ZDI-25-414/","label":"www.zerodayinitiative.com/advisories/ZDI-25-414/","hostname":"www.zerodayinitiative.com","tags":["X Research Advisory","REPORT","Third Party Advisory"]},{"url":"https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864","label":"github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101","hostname":"github.com","tags":["Vendor Advisory","WEB","Patch"]},{"url":"https://ubuntu.com/security/CVE-2025-6442","label":"ubuntu.com/security/CVE-2025-6442","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-6442","label":"www.cve.org/CVERecord?id=CVE-2025-6442","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://ubuntu.com/security/notices/USN-7709-1","label":"ubuntu.com/security/notices/USN-7709-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://ubuntu.com/security/notices/USN-7840-1","label":"ubuntu.com/security/notices/USN-7840-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2025-6442","label":"security-tracker.debian.org/tracker/CVE-2025-6442","hostname":"security-tracker.debian.org","tags":["Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-6442","label":"nvd.nist.gov/vuln/detail/CVE-2025-6442","hostname":"nvd.nist.gov","tags":["Advisory","Oval"]},{"url":"https://github.com/ruby/webrick","label":"github.com/ruby/webrick","hostname":"github.com","tags":["PACKAGE"]},{"url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/webrick/CVE-2025-6442.yml","label":"github.com/rubysec/ruby-advisory-db/blob/master/gems/webrick/CVE-2025-6442.yml","hostname":"github.com","tags":["WEB"]},{"url":"https://www.zerodayinitiative.com/advisories/ZDI-25-414","label":"www.zerodayinitiative.com/advisories/ZDI-25-414","hostname":"www.zerodayinitiative.com","tags":["WEB"]}],"lineage":{"upstream":[],"downstream":["SUSE-SU-2025:02739-1","SUSE-SU-2025:02739-2","SUSE-SU-2025:4264-1","USN-7840-1"],"duplicates":[],"related":["SUSE-SU-2025:02739-1","SUSE-SU-2025:02739-2","SUSE-SU-2025:4264-1","USN-7840-1"]},"timeline":[{"kind":"published","date":"2025-06-25T16:52:24.625Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2025-06-25T20:42:41.093Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":26,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T08:10:31.116Z","stale":false,"partial":false}}