Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Loofah versions 2.2.0 through 2.19.0 use recursion for sanitizing "CDATA" sections, making it susceptible to stack exhaustion and raising a SystemStackError exception. This may lead to a denial of service through CPU resource consumption. Users who are unable to upgrade may be able to mitigate this vulnerability by limiting the length of the strings that are sanitized.
CWE-674 - Uncontrolled Recursion
The product does not properly control the amount of recursion which takes place, consuming excessive resources, such as allocated memory or the program stack.