Http-proxy-middleware saw a minor version bump from 0.19.0 to 0.19.1, with the newer version released on November 25, 2018, while the older on August 29, 2018. While both maintain the core functionality as a one-liner proxy middleware for Connect, Express, and Browser-sync, subtle changes surface in their dependencies and devDependencies. The dependency lodash gets updated from version ^4.17.10 to ^4.17.11, indicating potentially bug fixes or minor improvements in lodash that http-proxy-middleware leverages.
Significant changes appear among the development dependencies. Notably, upgrades include ws, opn, chai, @commitlint/cli, and @commitlint/config-conventional. The introduction of prettier, precise-commits and the removal of snazzy and standard suggest a shift in code formatting and commit linting practices. Devs may appreciate that the newer release adopts prettier for code formatting, potentially leading to more consistent code style across contributions. It also includes husky for git hooks, which in the newer version is updated from 0.14.3 to 1.2.0. Finally, the slight increase in the unpacked size, from 47638 to 47749, could reflect included enhancements and expanded functionality testing, even as underlying functionality stays consistent.
All the vulnerabilities related to the version 0.19.1 of the package
Denial of service in http-proxy-middleware
Versions of the package http-proxy-middleware before 2.0.7, from 3.0.0 and before 3.0.3 are vulnerable to Denial of Service (DoS) due to an UnhandledPromiseRejection error thrown by micromatch. An attacker could kill the Node.js process and crash the server by making requests to certain paths.
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.
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.
