It was discovered that Rack did not properly structure regular expressions
in some of its parsing components, which could result in uncontrolled
resource consumption if an application using Rack received specially
crafted input. A remote attacker could possibly use this issue to cause a
denial of service. (CVE-2022-44570, CVE-2022-44571)
It was discovered that Rack did not properly structure regular expressions
in its multipart parsing component, which could result in uncontrolled
resource consumption if an application using Rack to parse multipart posts
received specially crafted input. A remote attacker could possibly use
this issue to cause a denial of service. This issue was only fixed in
Ubuntu 20.04 ESM and Ubuntu 22.04 ESM. (CVE-2022-44572)