CVE-2021-21317

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.

• CWE-400
• CWE-1333

• https://github.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96cPatch
• https://github.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4Third Party Advisory
• https://www.npmjs.com/package/uap-coreProduct, Third Party Advisory
• https://github.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96cPatch
• https://github.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4Third Party Advisory
• https://www.npmjs.com/package/uap-coreProduct, Third Party Advisory

Published

Feb 16, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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