Babel-loader is a crucial webpack loader that allows developers to transpile JavaScript files using Babel. This enables the use of next-generation JavaScript features in projects while maintaining compatibility with older browsers and environments. Comparing versions 6.2.9 and 6.2.8 reveals subtle but potentially impactful differences primarily in the development dependencies.
Notably, nyc, the code coverage tool, has been updated from version 9.0.0 to 10.0.0 in version 6.2.9. This suggests improvements in code coverage reporting and potentially better integration with continuous integration systems. While not directly affecting runtime behavior, enhanced testing infrastructure ensures code reliability and maintainability which is a valuable thing for developers.
Both versions maintain identical core functionalities, dependencies like mkdirp, loader-utils, object-assign, and find-cache-dir remain unchanged, indicating a stable core. The peer dependencies, namely webpack and babel-core, also remain consistent, ensuring backward compatibility with existing Babel and Webpack setups, which is a great thing.
Furthermore, the consistent listing of other devDependencies, like ava, eslint, rimraf, codecov, various Babel-related tools, and eslint-plugin-flowtype, implies a focus on maintaining code quality and consistency across versions. The release date difference (November 18th vs December 7th) marks the former as the previous stable release while the latter introduces improvements and potentially bug fixes accumulated during this period. When choosing Babel-loader versions, consider the updates to code coverage tools.
All the vulnerabilities related to the version 6.2.9 of the package
Prototype pollution in webpack loader-utils
Prototype pollution vulnerability in function parseQuery in parseQuery.js in webpack loader-utils prior to version 2.0.3 via the name variable in parseQuery.js.
Prototype Pollution in JSON5 via Parse Method
The parse method of the JSON5 library before and including version 2.2.1 does not restrict parsing of keys named __proto__, allowing specially crafted strings to pollute the prototype of the resulting object.
This vulnerability pollutes the prototype of the object returned by JSON5.parse and not the global Object prototype, which is the commonly understood definition of Prototype Pollution. However, polluting the prototype of a single object can have significant security impact for an application if the object is later used in trusted operations.
This vulnerability could allow an attacker to set arbitrary and unexpected keys on the object returned from JSON5.parse. The actual impact will depend on how applications utilize the returned object and how they filter unwanted keys, but could include denial of service, cross-site scripting, elevation of privilege, and in extreme cases, remote code execution.
This vulnerability is patched in json5 v2.2.2 and later. A patch has also been backported for json5 v1 in versions v1.0.2 and later.
Suppose a developer wants to allow users and admins to perform some risky operation, but they want to restrict what non-admins can do. To accomplish this, they accept a JSON blob from the user, parse it using JSON5.parse, confirm that the provided data does not set some sensitive keys, and then performs the risky operation using the validated data:
const JSON5 = require('json5');
const doSomethingDangerous = (props) => {
if (props.isAdmin) {
console.log('Doing dangerous thing as admin.');
} else {
console.log('Doing dangerous thing as user.');
}
};
const secCheckKeysSet = (obj, searchKeys) => {
let searchKeyFound = false;
Object.keys(obj).forEach((key) => {
if (searchKeys.indexOf(key) > -1) {
searchKeyFound = true;
}
});
return searchKeyFound;
};
const props = JSON5.parse('{"foo": "bar"}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
doSomethingDangerous(props); // "Doing dangerous thing as user."
} else {
throw new Error('Forbidden...');
}
If the user attempts to set the isAdmin key, their request will be rejected:
const props = JSON5.parse('{"foo": "bar", "isAdmin": true}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
doSomethingDangerous(props);
} else {
throw new Error('Forbidden...'); // Error: Forbidden...
}
However, users can instead set the __proto__ key to {"isAdmin": true}. JSON5 will parse this key and will set the isAdmin key on the prototype of the returned object, allowing the user to bypass the security check and run their request as an admin:
const props = JSON5.parse('{"foo": "bar", "__proto__": {"isAdmin": true}}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
doSomethingDangerous(props); // "Doing dangerous thing as admin."
} else {
throw new Error('Forbidden...');
}