The ZYREX POPUP WordPress plugin through 1.0 does not validate the type of files uploaded when creating a popup, allowing a high privileged user (such as an Administrator) to upload arbitrary files, even when modifying the file system is disallowed, such as in a multisite install.

The ZYREX POPUP WordPress plugin through 1.0 does not validate the type of files uploaded when creating a popup, allowing a high privileged user (such as an Administrator) to upload arbitrary files, even when modifying the file system is disallowed, such as in a multisite install.