jruby-complete 9.3.8.0 embeds a version of rexml at ./META-INF/jruby.home/lib/ruby/stdlib/rexml/ that is subject to CVE-2021-28965.

The REXML gem before 3.2.5 in Ruby before 2.6.7, 2.7.x before 2.7.3, and 3.x before 3.0.1 does not properly address XML round-trip issues. An incorrect document can be produced after parsing and serializing.