{"id":"CVE-2021-21317","aliases":["GHSA-p4pj-mg4r-x6v4"],"url":"https://o3.security/vulnerability/CVE-2021-21317","summary":"Denial of Service in uap-core","details":"uap-core in an open-source npm package which contains the core of BrowserScope's original user agent string parser. In uap-core before version 0.11.0, some regexes are vulnerable to regular expression denial of service (REDoS) due to overlapping capture groups. This allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to maliciously crafted long strings. This is fixed in version 0.11.0. Downstream packages such as uap-python, uap-ruby etc which depend upon uap-core follow different version schemes.","published":"2021-02-16T18:15:12.583Z","modified":"2026-07-09T10:52:45.323464Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"uap-core","fixedVersion":"0.11.0"}],"fix":{"url":"https://github.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96c","label":"ua-parser/uap-core@dc9925d"},"references":[{"type":"ADVISORY","url":"https://github.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4"},{"type":"ADVISORY","url":"https://www.npmjs.com/package/uap-core"},{"type":"FIX","url":"https://github.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96c"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T10:52:45.323464Z"}}