{"id":"UBUNTU-CVE-2021-41819","details":"CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names. This also affects the CGI gem through 0.3.0 for Ruby.","modified":"2026-04-22T13:01:29.912037Z","published":"2022-01-01T06:15:00Z","related":["USN-5235-1"],"upstream":["CVE-2021-41819"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-41819"},{"type":"REPORT","url":"https://www.ruby-lang.org/en/news/2021/11/24/cookie-prefix-spoofing-in-cgi-cookie-parse-cve-2021-41819/"},{"type":"REPORT","url":"https://github.com/ruby/cgi/commit/052eb3a828b0f99bca39cfd800f6c2b91307dbd5"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5235-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-41819"}],"affected":[{"package":{"name":"ruby2.3","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/ruby2.3@2.3.1-2~ubuntu16.04.16+esm2?arch=source&distro=esm-infra/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.1-2~ubuntu16.04.16+esm2"}]}],"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"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro","binaries":[{"binary_name":"libruby2.3","binary_version":"2.3.1-2~ubuntu16.04.16+esm2"},{"binary_name":"ruby2.3","binary_version":"2.3.1-2~ubuntu16.04.16+esm2"},{"binary_name":"ruby2.3-tcltk","binary_version":"2.3.1-2~ubuntu16.04.16+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-41819.json"}},{"package":{"name":"ruby2.5","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/ruby2.5@2.5.1-1ubuntu1.11?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.1-1ubuntu1.11"}]}],"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"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libruby2.5","binary_version":"2.5.1-1ubuntu1.11"},{"binary_name":"ruby2.5","binary_version":"2.5.1-1ubuntu1.11"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-41819.json"}},{"package":{"name":"ruby2.7","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/ruby2.7@2.7.0-5ubuntu1.6?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.7.0-5ubuntu1.6"}]}],"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"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libruby2.7","binary_version":"2.7.0-5ubuntu1.6"},{"binary_name":"ruby2.7","binary_version":"2.7.0-5ubuntu1.6"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-41819.json"}},{"package":{"name":"ruby3.0","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/ruby3.0@3.0.2-7ubuntu2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.0.2-7ubuntu2"}]}],"versions":["3.0.2-5ubuntu1","3.0.2-7"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"3.0.2-7ubuntu2","binary_name":"libruby3.0"},{"binary_name":"ruby3.0","binary_version":"3.0.2-7ubuntu2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-41819.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}