Description

Shescape has potential environment variable exposure on Windows with CMD

Impact

This impact users of Shescape on Windows that explicitly configure shell: 'cmd.exe' or shell: true using any of quote/quoteAll/escape/escapeAll.

An attacker may be able to get read-only access to environment variables. Example:

import * as cp from "node:child_process";
import { Shescape } from "shescape";

// 1. Prerequisites
const shescape = new Shescape({
    shell: "cmd.exe",
    // Or
    shell: true, // Only if the default shell is CMD...
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For Shescape prior to v2.0.0, the options object must have shell: 'cmd.exe' or shell: undefined and interpolation: true.

Patches

This bug has been patched in v2.1.2 which you can upgrade to now.

If you are already using v2 of Shescape, no further changes are required. If you are using v1 of Shescape, follow the migration guide to upgrade to v2. There is no plan to release a patch compatible with v1 of Shescape.

Workarounds

Alternatively, users can remove all instances of % from user input before using Shescape.

References

Shescape Pull Request #1916

Shescape commit 0a81f1e

Shescape release v2.1.2

For more information

Comment on Pull Request #1916

Comment on commit 0a81f1e

Open an issue at https://github.com/ericcornelissen/shescape/issues (New issue > Question)

Mitigation

Aliases

References