{"id":"CVE-2018-20164","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-20164","generatedAt":"2026-10-28T21:16:50.530Z","title":"A Regular Expression Denial of Service (ReDoS) issue allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to a value containing a long digit string.","description":"An issue was discovered in regex.yaml (aka regexes.yaml) in UA-Parser UAP-Core before 0.6.0. A Regular Expression Denial of Service (ReDoS) issue allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to a value containing a long digit string. (The UAP-Core project contains the vulnerability, propagating to all implementations.)","published":"2019-02-13T14:29:00.000Z","lastModified":"2026-06-17T01:52:23.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.0","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"cwe":["CWE-185"],"affected":["uaparser/user agent parser-core"],"epss":{"score":0.03298,"percentile":0.88449,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (3.30%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/ua-parser/uap-core/commit/010ccdc7303546cd22b9da687c29f4a996990014","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/ua-parser/uap-core/commit/156f7e12b215bddbaf3df4514c399d683e6cdadc","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/ua-parser/uap-core/issues/332","source":"cve@mitre.org"},{"url":"https://www.x41-dsec.de/lab/advisories/x41-2018-009-uaparser/","tags":["Exploit","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/ua-parser/uap-core/commit/010ccdc7303546cd22b9da687c29f4a996990014","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/ua-parser/uap-core/commit/156f7e12b215bddbaf3df4514c399d683e6cdadc","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/ua-parser/uap-core/issues/332","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.x41-dsec.de/lab/advisories/x41-2018-009-uaparser/","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-20164","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}