Micromatch is a popular JavaScript library designed for glob matching, offering a faster and more efficient alternative to minimatch and multimatch. Version 2.1.6 builds upon the solid foundation of its predecessor, 2.1.5, with a key distinction found within its dependencies. While both versions share a vast majority of dependencies, including essential packages like debug, braces, is-glob, and kind-of, a notable change lies in the regex-cache dependency. Version 2.1.6 upgrades to regex-cache version 0.4.0 from 0.3.0 in version 2.1.5. This seemingly minor update may incorporate performance enhancements, bug fixes, or new features within the regex caching mechanism, which could lead to improved matching speeds and more reliable globbing results within micromatch.
For developers, Micromatch simplifies file and path matching using glob patterns familiar from shell environments. Its core functionality revolves around two primary methods: micromatch.isMatch(), a direct replacement for minimatch(), which checks if a given string matches a glob pattern, and micromatch(), which serves as a substitute for multimatch(), filtering an array of strings based on one or more glob patterns. This library is used for matching file paths, filtering lists, or verifying input against defined patterns, making it a valuable tool for build processes, task runners, and various other automation scenarios in Node.js and JavaScript projects. The slight change in regex-cache hints at an evolution towards better runtime glob processing.
All the vulnerabilities related to the version 2.1.6 of the package
Regular Expression Denial of Service (ReDoS) in micromatch
The NPM package micromatch prior to version 4.0.8 is vulnerable to Regular Expression Denial of Service (ReDoS). The vulnerability occurs in micromatch.braces() in index.js because the pattern .* will greedily match anything. By passing a malicious payload, the pattern matching will keep backtracking to the input while it doesn't find the closing bracket. As the input size increases, the consumption time will also increase until it causes the application to hang or slow down. There was a merged fix but further testing shows the issue persisted prior to https://github.com/micromatch/micromatch/pull/266. This issue should be mitigated by using a safe pattern that won't start backtracking the regular expression due to greedy matching.
Regular Expression Denial of Service (ReDoS) in braces
A vulnerability was found in Braces versions prior to 2.3.1. Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) attacks.
Regular Expression Denial of Service in braces
Versions of braces prior to 2.3.1 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.
Upgrade to version 2.3.1 or higher.
Uncontrolled resource consumption in braces
The NPM package braces fails to limit the number of characters it can handle, which could lead to Memory Exhaustion. In lib/parse.js, if a malicious user sends "imbalanced braces" as input, the parsing will enter a loop, which will cause the program to start allocating heap memory without freeing it at any moment of the loop. Eventually, the JavaScript heap limit is reached, and the program will crash.
