Version Details and Security Vulnerabilities

A Regular Expression Denial of Service (ReDoS) flaw was found in kangax html-minifier 4.0.0 because of the reCustomIgnore regular expression.

Version of clean-css prior to 4.1.11 are vulnerable to Regular Expression Denial of Service (ReDoS). Untrusted input may cause catastrophic backtracking while matching regular expressions. This can cause the application to be unresponsive leading to Denial of Service.

Recommendation

Upgrade to version 4.1.11 or higher.

In the npm package color-string, there is a ReDos (Regular Expression Denial of Service) vulnerability regarding an exponential time complexity for linearly increasing input lengths for hwb() color strings.

Strings reaching more than 5000 characters would see several milliseconds of processing time; strings reaching more than 50,000 characters began seeing 1500ms (1.5s) of processing time.

The cause was due to a the regular expression that parses hwb() strings - specifically, the hue value - where the integer portion of the hue value used a 0-or-more quantifier shortly thereafter followed by a 1-or-more quantifier.

This caused excessive backtracking and a cartesian scan, resulting in exponential time complexity given a linear increase in input length.