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.