The isMail transport in PHPMailer before 5.2.20 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code by leveraging improper interaction between the escapeshellarg function and internal escaping performed in the mail function in PHP. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-10033.

Affected: Packagist: phpmailer/phpmailer

### Impact The `isMail` transport in PHPMailer before 5.2.20 might allow remote attackers to pass extra parameters to the `mail` command and consequently execute arbitrary code by leveraging improper interaction between the `escapeshellarg` function and internal escaping performed in the mail function in PHP. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-10033.

This issue really emphasises that it's worth avoiding the built-in PHP `mail()` function entirely.

### Patches Fixed in 5.2.20

### Workarounds Send via SMTP to localhost instead of calling the `mail()` function.

### References https://nvd.nist.gov/vuln/detail/CVE-2016-10045 See also https://nvd.nist.gov/vuln/detail/CVE-2016-10033

### For more information If you have any questions or comments about this advisory: * Open a private issue in [the PHPMailer project](https://github.com/PHPMailer/PHPMailer)

Affected: Ubuntu:Pro:16.04:LTS: libphp-phpmailer

The isMail transport in PHPMailer before 5.2.20 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code by leveraging improper interaction between the escapeshellarg function and internal escaping performed in the mail function in PHP. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-10033.