ua-parser-js >= 0.7.14, fixed in 0.7.24, uses a regular expression which is vulnerable to denial of service. If an attacker sends a malicious User-Agent header, ua-parser-js will get stuck processing it for an extended period of time.
https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14
https://github.com/faisalman/ua-parser-js/commit/809439e20e273ce0d25c1d04e111dcf6011eb566
https://gist.github.com/b-c-ds/6941d80d6b4e694df4bc269493b7be76