WEBrick::HTTPAuth::DigestAuth in Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 has a regular expression Denial of Service cause by looping/backtracking. A victim must expose a WEBrick server that uses DigestAuth to the Internet or a untrusted network. CREATE(Triage):(User=admin) [CVE-2019-16201|https://nvd.nist.gov/vuln/detail/CVE-2019-16201]