{"id":"UBUNTU-CVE-2025-6442","details":"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. The 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.","modified":"2026-05-20T16:23:42.167812366Z","published":"2025-06-25T17:15:00Z","related":["USN-7709-1","USN-7840-1"],"upstream":["CVE-2025-6442"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-6442"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-6442"},{"type":"REPORT","url":"https://www.zerodayinitiative.com/advisories/ZDI-25-414/"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-7709-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-7840-1"}],"affected":[{"package":{"name":"jruby","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/jruby?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.6-5ubuntu1","1.5.6-6","1.5.6-7","1.5.6-9+deb8u2build0.14.04.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"jruby","binary_version":"1.5.6-9+deb8u2build0.14.04.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"jruby","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/jruby?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.21-2ubuntu4","1.7.22-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"jruby","binary_version":"1.7.22-1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby2.3","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/ruby2.3?arch=source&distro=esm-infra%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.1-2~ubuntu16.04.16+esm11"}]}],"versions":["2.3.0-1","2.3.0-2","2.3.0-4ubuntu2","2.3.0-4ubuntu3","2.3.0-5ubuntu1","2.3.1-2~16.04","2.3.1-2~16.04.2","2.3.1-2~16.04.4","2.3.1-2~16.04.5","2.3.1-2~16.04.6","2.3.1-2~16.04.7","2.3.1-2~16.04.9","2.3.1-2~16.04.10","2.3.1-2~16.04.11","2.3.1-2~16.04.12","2.3.1-2~ubuntu16.04.13","2.3.1-2~ubuntu16.04.14","2.3.1-2~ubuntu16.04.15","2.3.1-2~ubuntu16.04.16","2.3.1-2~ubuntu16.04.16+esm1","2.3.1-2~ubuntu16.04.16+esm2","2.3.1-2~ubuntu16.04.16+esm3","2.3.1-2~ubuntu16.04.16+esm4","2.3.1-2~ubuntu16.04.16+esm5","2.3.1-2~ubuntu16.04.16+esm6","2.3.1-2~ubuntu16.04.16+esm7","2.3.1-2~ubuntu16.04.16+esm8","2.3.1-2~ubuntu16.04.16+esm9","2.3.1-2~ubuntu16.04.16+esm10"],"ecosystem_specific":{"binaries":[{"binary_version":"2.3.1-2~ubuntu16.04.16+esm11","binary_name":"libruby2.3"},{"binary_name":"ruby2.3","binary_version":"2.3.1-2~ubuntu16.04.16+esm11"},{"binary_name":"ruby2.3-tcltk","binary_version":"2.3.1-2~ubuntu16.04.16+esm11"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby2.5","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/ruby2.5?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.1-1ubuntu1.16+esm6"}]}],"versions":["2.5.0~preview1-1ubuntu2","2.5.0-4ubuntu1","2.5.0-4ubuntu4","2.5.0-5ubuntu1","2.5.0-6ubuntu1","2.5.1-1ubuntu1","2.5.1-1ubuntu1.1","2.5.1-1ubuntu1.2","2.5.1-1ubuntu1.4","2.5.1-1ubuntu1.5","2.5.1-1ubuntu1.6","2.5.1-1ubuntu1.7","2.5.1-1ubuntu1.8","2.5.1-1ubuntu1.9","2.5.1-1ubuntu1.10","2.5.1-1ubuntu1.11","2.5.1-1ubuntu1.12","2.5.1-1ubuntu1.13","2.5.1-1ubuntu1.14","2.5.1-1ubuntu1.15","2.5.1-1ubuntu1.16","2.5.1-1ubuntu1.16+esm1","2.5.1-1ubuntu1.16+esm3","2.5.1-1ubuntu1.16+esm4","2.5.1-1ubuntu1.16+esm5"],"ecosystem_specific":{"binaries":[{"binary_name":"libruby2.5","binary_version":"2.5.1-1ubuntu1.16+esm6"},{"binary_version":"2.5.1-1ubuntu1.16+esm6","binary_name":"ruby2.5"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"jruby","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/jruby?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.1.13.0-1","9.1.17.0-1~18.04"],"ecosystem_specific":{"binaries":[{"binary_name":"jruby","binary_version":"9.1.17.0-1~18.04"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby2.7","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/ruby2.7?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.7.0-5ubuntu1.18+esm3"}]}],"versions":["2.7.0-1","2.7.0-2","2.7.0-3","2.7.0-4","2.7.0-4ubuntu1","2.7.0-5ubuntu1","2.7.0-5ubuntu1.1","2.7.0-5ubuntu1.2","2.7.0-5ubuntu1.3","2.7.0-5ubuntu1.4","2.7.0-5ubuntu1.5","2.7.0-5ubuntu1.6","2.7.0-5ubuntu1.7","2.7.0-5ubuntu1.8","2.7.0-5ubuntu1.9","2.7.0-5ubuntu1.10","2.7.0-5ubuntu1.11","2.7.0-5ubuntu1.12","2.7.0-5ubuntu1.13","2.7.0-5ubuntu1.14","2.7.0-5ubuntu1.15","2.7.0-5ubuntu1.16","2.7.0-5ubuntu1.17","2.7.0-5ubuntu1.18","2.7.0-5ubuntu1.18+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libruby2.7","binary_version":"2.7.0-5ubuntu1.18+esm3"},{"binary_version":"2.7.0-5ubuntu1.18+esm3","binary_name":"ruby2.7"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"jruby","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/jruby?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.1.17.0-3","9.1.17.0-3build5","9.1.17.0-3build6"],"ecosystem_specific":{"binaries":[{"binary_version":"9.1.17.0-3build6","binary_name":"jruby"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby-webrick","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/ruby-webrick?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.7.0-3ubuntu0.2"}]}],"versions":["1.7.0-1","1.7.0-2","1.7.0-3","1.7.0-3ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-webrick","binary_version":"1.7.0-3ubuntu0.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby-webrick","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/ruby-webrick?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.1-1ubuntu0.2"}]}],"versions":["1.8.1-1","1.8.1-1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-webrick","binary_version":"1.8.1-1ubuntu0.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby-webrick","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/ruby-webrick?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.1-1"}]}],"versions":["1.8.1-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.9.1-1","binary_name":"ruby-webrick"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}},{"package":{"name":"ruby-webrick","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/ruby-webrick?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.1-1"}]}],"ecosystem_specific":{"binaries":[{"binary_version":"1.9.1-1","binary_name":"ruby-webrick"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-6442.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}