{"id":"CVE-2025-27220","aliases":["GHSA-mhwm-jh88-3gjf"],"url":"https://o3.security/vulnerability/CVE-2025-27220","summary":"CGI has Regular Expression Denial of Service (ReDoS) potential in Util#escapeElement","details":"There is a possibility for Regular expression Denial of Service (ReDoS) by in the cgi gem. This vulnerability has been assigned the CVE identifier CVE-2025-27220. We recommend upgrading the cgi gem.\n\n## Details\n\nThe regular expression used in `CGI::Util#escapeElement` is vulnerable to ReDoS. The crafted input could lead to a high CPU consumption.\n\nThis vulnerability only affects Ruby 3.1 and 3.2. If you are using these versions, please update CGI gem to version 0.3.5.1, 0.3.7, 0.4.2 or later.\n\n## Affected versions\n\ncgi gem versions <= 0.3.5, 0.3.6, 0.4.0 and 0.4.1.\n\n## Credits\n\nThanks to svalkanov for discovering this issue.\nAlso thanks to nobu for fixing this vulnerability.","published":"2025-03-03T00:00:00Z","modified":"2026-10-28T02:31:13.567875861Z","cvss":{"score":4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L"},"epss":{"score":0.00745,"percentile":0.5303,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"cgi","fixedVersion":"0.3.5.1"},{"ecosystem":"RubyGems","name":"cgi","fixedVersion":"0.3.7"},{"ecosystem":"RubyGems","name":"cgi","fixedVersion":"0.4.2"}],"fix":{"url":"https://github.com/ruby/cgi/pull/52","label":"ruby/cgi#52"},"references":[{"type":"WEB","url":"https://hackerone.com/reports/2890322"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00008.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/27xxx/CVE-2025-27220.json"},{"type":"ADVISORY","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2025-27220.yml"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-27220"},{"type":"WEB","url":"https://github.com/ruby/cgi/pull/52"},{"type":"WEB","url":"https://github.com/ruby/cgi/pull/53"},{"type":"WEB","url":"https://github.com/ruby/cgi/pull/54"},{"type":"PACKAGE","url":"https://github.com/ruby/cgi"},{"type":"WEB","url":"https://www.cve.org/CVERecord?id=CVE-2025-27220"},{"type":"WEB","url":"https://www.ruby-lang.org/en/news/2025/02/26/security-advisories"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:13.567875861Z"}}