GHSA-m298-fh5c-jc66

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GHSA-m298-fh5c-jc66

Summary: Object injection in PHPMailer/PHPMailer

Details: ### Impact This is a reintroduction of an earlier issue (CVE-2018-19296) by an unrelated bug fix in PHPMailer 6.1.8. An external file may be unexpectedly executable if it is used as a path to an attachment file via PHP's support for `.phar` files. Exploitation requires that an attacker is able to provide an unfiltered path to a file to attach, or to trick calling code into generating one. See [this article](https://knasmueller.net/5-answers-about-php-phar-exploitation) for more info. ### Patches This issue was patched in the PHPMailer 6.4.1 release. This release also implements stricter filtering for attachment paths; paths that look like *any* kind of URL are rejected. ### Workarounds Validate paths to loaded files using the same pattern as used in [`isPermittedPath()`](https://github.com/PHPMailer/PHPMailer/blob/master/src/PHPMailer.php#L1815) before using them in *any* PHP file function, such as `file_exists`. This method can't be used directly because it is protected, but you can implement the same thing in calling code. Note that this should be applied to *all* user-supplied paths passed into such functions; it's not a problem specific to PHPMailer. ### Credit This issue was found by [Fariskhi Vidyan](https://github.com/farisv), reported and managed via Tidelift.

References: https://github.com/PHPMailer/PHPMailer/security/advisories/GHSA-m298-fh5c-jc66, https://nvd.nist.gov/vuln/detail/CVE-2020-36326, https://github.com/PHPMailer/PHPMailer/commit/e2e07a355ee8ff36aba21d0242c5950c56e4c6f9, https://github.com/FriendsOfPHP/security-advisories/blob/master/phpmailer/phpmailer/CVE-2020-36326.yaml, https://github.com/PHPMailer/PHPMailer, https://github.com/PHPMailer/PHPMailer/releases/tag/v6.4.1, https://lists.fedoraproject.org/archives/list/[email protected]/message/3B5WDPGUFNPG4NAZ6G4BZX43BKLAVA5B, https://lists.fedoraproject.org/archives/list/[email protected]/message/KPU66INRFY5BQ3ESVPRUXJR4DXQAFJVT