React Syntax Highlighter is a component that allows you to add syntax highlighting to your React applications using either PrismJS or Highlight.js. Both versions 12.0.1 and 12.0.2 share the same core dependencies, including PrismJS, Lowlight, Refractor, Highlight.js, and Babel runtime. This means the essential functionality remains the same: excellent syntax highlighting with various language support and themes. They both have the same dev dependencies used for building, testing, and maintaining the package, such as Webpack, Babel, Jest, and Prettier revealing a consistent development workflow. Crucially, the peer dependency on React remains at ">= 0.14.0," ensuring backward compatibility for a wide range of React projects.
The key difference between version 12.0.1 and 12.0.2 lies solely in the release date. Version 12.0.2 was published just a few minutes after 12.0.1. Since the dependencies, file count, and unpacked size are identical, version 12.0.2 likely contains minor bug fixes, dependency updates, or improvements, without introducing major breaking changes or new features.
For developers, this indicates a high level of stability in the library. Updating from 12.0.1 to 12.0.2 should be safe and straightforward. Regularly updating to the latest patch version helps to incorporate any bug fixes or minor enhancements, ensuring a smoother development.
All the vulnerabilities related to the version 12.0.2 of the package
ReDOS vulnerabities: multiple grammars
The Regular expression Denial of Service (ReDoS) is a Denial of Service attack, that exploits the fact that most Regular Expression implementations may reach extreme situations that cause them to work very slowly (exponentially related to input size). An attacker can then cause a program using a Regular Expression to enter these extreme situations and then hang for a very long time.
If are you are using Highlight.js to highlight user-provided data you are possibly vulnerable. On the client-side (in a browser or Electron environment) risks could include lengthy freezes or crashes... On the server-side infinite freezes could occur... effectively preventing users from accessing your app or service (ie, Denial of Service).
This is an issue with grammars shipped with the parser (and potentially 3rd party grammars also), not the parser itself. If you are using Highlight.js with any of the following grammars you are vulnerable. If you are using highlightAuto to detect the language (and have any of these grammars registered) you are vulnerable. Exponential grammars (C, Perl, JavaScript) are auto-registered when using the common grammar subset/library require('highlight.js/lib/common') as of 10.4.0 - see https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@10.4.0/build/highlight.js
All versions prior to 10.4.1 are vulnerable, including version 9.18.5.
Grammars with exponential backtracking issues:
And of course any aliases of those languages have the same issue. ie: hpp is no safer than cpp.
Grammars with polynomial backtracking issues:
And again: any aliases of those languages have the same issue. ie: ruby and rb share the same ruby issues.
If you have any questions or comments about this advisory:
Prototype Pollution in highlight.js
Affected versions of this package are vulnerable to Prototype Pollution. A malicious HTML code block can be crafted that will result in prototype pollution of the base object's prototype during highlighting. If you allow users to insert custom HTML code blocks into your page/app via parsing Markdown code blocks (or similar) and do not filter the language names the user can provide you may be vulnerable.
The pollution should just be harmless data but this can cause problems for applications not expecting these properties to exist and can result in strange behavior or application crashes, i.e. a potential DOS vector.
If your website or application does not render user provided data it should be unaffected.
Versions 9.18.2 and 10.1.2 and newer include fixes for this vulnerability. If you are using version 7 or 8 you are encouraged to upgrade to a newer release.
Manually patch your library to create null objects for both languages and aliases:
const HLJS = function(hljs) {
// ...
var languages = Object.create(null);
var aliases = Object.create(null);
Filter the language names that users are allowed to inject into your HTML to guarantee they are valid.
If you have any questions or comments about this advisory: