PHPCSUtils is a suite of utility functions for use with PHP_CodeSniffer. From 1.0.0-alpha1 until 1.2.3, PHPCSUtils\AbstractSniffs\AbstractArrayDeclarationSniff::getActualArrayKey() evaluates attacker-controlled array-key expressions with eval(), allowing callback-form keys in untrusted PHP code scanned by an extending sniff to execute arbitrary commands on the scanning host. Known reachable paths include Universal.Arrays.DuplicateArrayKey and Universal.Arrays.MixedArrayKeyTypes. This issue is fixed in version 1.2.3.

Affected: Packagist: phpcsstandards/phpcsutils

### Impact

PHPCSUtils versions 1.0.0-alpha1 through 1.2.2 contain an arbitrary code execution vulnerability in `PHPCSUtils\AbstractSniffs\AbstractArrayDeclarationSniff::getActualArrayKey()`. The vulnerable method is reached by any sniff that extends `AbstractArrayDeclarationSniff` and calls `getActualArrayKey()`.

Running PHPCS over untrusted PHP code through such a sniff, for example, in a CI pipeline that lints pull requests, or on a developer machine reviewing third-party code, could lead to arbitrary command execution on the scanning host.

The vulnerability happens when the method determines the value of an array key using `eval()`. A maliciously crafted array key such as `'system'('id')` would be executed when the code was scanned.

### Known attack vectors

Known code paths that reach the vulnerable method include the following PHPCSExtra sniffs:

- `Universal.Arrays.DuplicateArrayKey` - `Universal.Arrays.MixedArrayKeyTypes`

Other packages that call `AbstractArrayDeclarationSniff::getActualArrayKey()` may also be vulnerable.

### Patches

This issue has been fixed in PHPCSUtils 1.2.3. We recommend all users upgrade to 1.2.3 or later.

### Workaround

Users who cannot upgrade immediately can disable the sniffs that reach the vulnerable method by adding `<exclude>` tags to their custom ruleset (replace the placeholder standard and sniff names with the ones used in your setup):

```xml <rule ref="Standard"> <exclude name="Standard.Category.SniffName"/> </rule> ```

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