REXML is an XML toolkit for Ruby. The REXML gem before 3.3.2 has some DoS vulnerabilities when it parses an XML that has many specific characters such as whitespace character, `>]` and `]>`. The REXML gem 3.3.3 or later include the patches to fix these vulnerabilities.

A flaw was found in the REXML package. Reading an XML file that contains many entity expansions may lead to a denial of service due to resource starvation. An attacker can use this flaw to trick a user into processing an untrusted XML file.

A vulnerability was found in REXML RubyGems. This package is vulnerable to denial of service (DoS) when parsing a deep XML structure with the same local name attribute. This vulnerability only affects tree parser API like REXML::Document.new, other parser APIs such as stream parser API and SAX2 parser API are not affected.