OS command injection in the npm package loading component in AWS jsii-diff before 1.131.0 might allow context-dependent attackers to execute arbitrary commands via crafted package specifiers passed to the npm: source argument.

To mitigate this issue, users should upgrade to jsii-diff v1.131.0 or later.

Affected: npm: jsii-diff

## Summary

jsii-diff is a command line tool to compare the API differences between two jsii assemblies, and report errors if there are backwards-incompatible changes to the API. An issue exists where specially formatted command line arguments can be used to execute shell commands via this tool.

## Impact jsii-diff supports downloading packages to compare directly from NPM, so that you can compare a proposed candidate version of your jsii package with an already-published version, by passing an argument that looks like `npm:<package-specifier>`. For example:

``` jsii-diff npm:my-package@latest . ```

By injecting a `;` into the `package-specifier` part of that command, jsii-diff can be tricked into running shell commands. For example:

``` jsii-diff "npm:lodash; touch /tmp/123" . ```

This allows anyone that can control the command-line arguments to jsii-diff to run arbitrary commands with the same permissions as the jsii-diff command itself.

## Patches This issue has been addressed in jsii-diff version 1.131.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

## Workarounds If you are unable to update, make sure only trusted actors can control the arguments passed to jsii-diff.

## References If you have any questions or comments about this advisory, AWS asks that you contact AWS Security via the [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or direc…