{"id":"CVE-2021-41819","aliases":["BIT-ruby-2021-41819","BIT-ruby-min-2021-41819","GHSA-4vf4-qmvg-mh7h"],"url":"https://o3.security/vulnerability/CVE-2021-41819","summary":"Cookie Prefix Spoofing in CGI::Cookie.parse","details":"CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names. This also affects the CGI gem prior to versions 0.3.1, 0.2.1, 0.1.1, and 0.1.0.1 for Ruby.","published":"2022-01-01T06:15:07.293Z","modified":"2026-09-16T08:29:31.902211Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"epss":{"score":0.02931,"percentile":0.86419,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"RubyGems","name":"cgi","fixedVersion":"0.3.1"},{"ecosystem":"RubyGems","name":"cgi","fixedVersion":"0.2.1"},{"ecosystem":"RubyGems","name":"cgi","fixedVersion":"0.1.0.1"}],"fix":null,"references":[{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUXQCH6FRKANCVZO2Q7D2SQX33FP3KWN/"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UTOJGS5IEFDK3UOO7IY4OTTFGHGLSWZF/"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202401-27"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20220121-0003/"},{"type":"REPORT","url":"https://hackerone.com/reports/910552"},{"type":"EVIDENCE","url":"https://www.ruby-lang.org/en/news/2021/11/24/cookie-prefix-spoofing-in-cgi-cookie-parse-cve-2021-41819/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-41819"},{"type":"PACKAGE","url":"https://github.com/ruby/cgi"},{"type":"WEB","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2021-41819.yml"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUXQCH6FRKANCVZO2Q7D2SQX33FP3KWN"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UTOJGS5IEFDK3UOO7IY4OTTFGHGLSWZF"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IUXQCH6FRKANCVZO2Q7D2SQX33FP3KWN"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UTOJGS5IEFDK3UOO7IY4OTTFGHGLSWZF"},{"type":"WEB","url":"https://security.netapp.com/advisory/ntap-20220121-0003"},{"type":"WEB","url":"https://www.ruby-lang.org/en/news/2021/11/24/cookie-prefix-spoofing-in-cgi-cookie-parse-cve-2021-41819"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-16T08:29:31.902211Z"}}