Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Arbitrary code execution is possible in reduce-css-calc node module <=1.2.4 through crafted css. This makes cross sites scripting (XSS) possible on the client and arbitrary code injection possible on the server and user input is passed to the `calc` function.
CWE-79 - Cross Site Scripting
Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.