include/functions_installer.inc.php in Serendipity through 2.0.5 is vulnerable to File Inclusion and a possible Code Execution attack during a first-time installation because it fails to sanitize the dbType POST parameter before adding it to an include() call in the bundled-libs/serendipity_generateFTPChecksums.php file.
https://github.com/s9y/Serendipity/issues/433
https://github.com/s9y/Serendipity/commit/bba6a840f4d53cbaf62971a3078a98c8ddf92b85