Expect, a core assertion library used extensively within the Jest testing framework, underwent a minor version update from 23.2.0 to 23.3.0, introducing subtle yet potentially important changes for developers. Both versions maintain the same core purpose: providing the expect function for writing readable and effective tests, fully documented on the Jest website.
A key difference lies within the dependencies. Expect 23.3.0 updates specific internal utilities. The most notable change is upgrading jest-regex-util from version 23.0.0 observed in *expect@23.2.0* to version 23.3.0. A bump in version is also present on jest-message-util from version 23.2.0 to 23.3.0 on the newer version. Other dependencies such as jest-diff, ansi-styles, jest-get-type, and jest-matcher-utils remain consistent between the two versions. While detailed changelogs for these internal packages should be referenced for specific fixes and features, developers should be aware of potential minor behavioral differences or bug fixes related to regex matching and message formatting within assertions. The unpacked size of the package also slightly increases from 1,100,455 bytes in version 23.2.0 to 1,102,107 bytes in version 23.3.0, suggesting added functionality or code adjustments within the dependency updates. Finally, Expect 23.3.0 was released on July 4th, 2018, after version 23.2.0 release on June 25th, 2018. Developers should evaluate if these changes justify an upgrade, especially if relying heavily on regular expressions or custom message assertions.
All the vulnerabilities related to the version 23.3.0 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.
