PHPMailer 6.4.1 contains a possible remote code execution vulnerability through the $langpath parameter of the setLanguage() method. If the $langpath parameter is passed unfiltered from user input, it can be set to a UNC path, and if an attacker is also able to create a remote mount on the server that the UNC path points to, a script file under their control may be executed.

Impact Arbitrary code may be run by a remote attacker under the web server or PHP process running on Window hosts.

Patches Mitigated in PHPMailer 6.5.0 by no longer treating translation files as PHP code, but by parsing their text content directly. This approach avoids the possibility of executing unknown code while retaining backward compatibility. This isn't ideal, so the current translation format is deprecated and will be replaced in the next major release.

Workarounds Any of: Ensure that calling code does not pass unfiltered user-supplied data to the $langpath parameter of the setLanguage() method. Block or filter the use of unknown UNC paths in this parameter (or altogether). Ensure that unauthorised users do not have the ability to read from unknown remote servers via UNC paths. Run on an OS that does not support UNC paths

References CVE-2021-34551.

Reported by listensec.com via Tidelift.

For more information If you have any questions or comments about this advisory: Open an issue in PHPMailer Email the maintainers

If a function is defined that has the same name as the default built-in email address validation scheme (php), it will be called in default configuration as when no validation scheme is provided, the default scheme's callable php was being called. If an attacker is able to inject such a function into the application (a much bigger issue), it will be called whenever an email address is validated, such as when calling validateAddress().

Impact Low impact – exploitation requires that an attacker can already inject code into an application, but it provides a trigger pathway.

Patches This is patched in PHPMailer 6.5.0 by denying the use of simple strings as validator function names, which is a very minor BC break.

Workarounds Inject your own email validator function.

References Reported by Vikrant Singh Chauhan via huntr.dev. CVE-2021-3603

For more information If you have any questions or comments about this advisory: Open an issue in the PHPMailer project Email us.

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 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() before using them in any PHP file function, such as fileexists. 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, reported and managed via Tidelift.

Last updated 24 July 2024

Last updated 24 July 2024

Last updated 24 July 2024

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

Impact The mailSend function in the default isMail transport in PHPMailer before 5.2.18 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code via a \" (backslash double quote) in a crafted Sender property.

Patches Fixed in 5.2.18

Workarounds Filter and validate user input before passing it to internal functions.

References https://nvd.nist.gov/vuln/detail/CVE-2016-10033 Related to a follow-on issue in https://nvd.nist.gov/vuln/detail/CVE-2016-10045

For more information If you have any questions or comments about this advisory: Open a private issue in the PHPMailer project

An issue was discovered in PHPMailer before 5.2.22. PHPMailer's msgHTML method applies transformations to an HTML document to make it usable as an email message body. One of the transformations is to convert relative image URLs into attachments using a script-provided base directory. If no base directory is provided, it resolves to /, meaning that relative image URLs get treated as absolute local file paths and added as attachments. To form a remote vulnerability, the msgHTML method must be called, passed an unfiltered, user-supplied HTML document, and must not set a base directory.

Multiple CRLF injection vulnerabilities