phpMussel from versions 1.0.0 and less than 1.6.0 has an unserialization vulnerability in PHP's phar wrapper. Uploading a specially crafted file to an affected version allows arbitrary code execution (discovered, tested, and confirmed by myself), so the risk factor should be regarded as very high. Newer phpMussel versions don't use PHP's phar wrapper, and are therefore unaffected. This has been fixed in version 1.6.0.

Affected: Packagist: phpmussel/phpmussel, Packagist: maikuolan/phpmussel

### Impact _What kind of vulnerability is it? Who is impacted?_

Anyone using >= v1.0.0 < v1.6.0.

### Patches _Has the problem been patched? What versions should users upgrade to?_

Yes. Upgrading to at least >= v1.6.0 (the earliest safe version) will resolve the problem. However, as multiple new major versions have been released since that version, upgrading to the latest available version is recommended, in order to protect against any potential future vulnerabilities, unknown at the time of writing this advisory.

### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_

Yes. In the package's configuration, disable archive checking by setting `check_archives` to `false` (thus avoiding execution of the affected parts of the codebase entirely).

### References _Are there any links users can visit to find out more?_

Yes. The vulnerability is documented at [SECURITY.md](https://github.com/phpMussel/phpMussel/security/policy) and also at [#167](https://github.com/phpMussel/phpMussel/issues/167).

### For more information If you have any questions or comments about this advisory: * Comment at the issue linked to this advisory, or.. * Contact [the package author](https://github.com/Maikuolan).