Prism is a syntax highlighting library. Starting with version 1.14.0 and prior to version 1.27.0 Prism's command line plugin can be used by attackers to achieve a cross-site scripting attack. The command line plugin did not properly escape its output leading to the input text being inserted into the DOM as HTML code. Server-side usage of Prism is not impacted. Websites that do not use the Command Line plugin are also not impacted. This bug has been fixed in v1.27.0. As a workaround do not use the command line plugin on untrusted inputs or sanitize all code blocks (remove all HTML code text) from all code blocks that use the command line plugin.