The following code produces a segmentation fault (11). Independantly the two lines act properly, but together they produce the segmentation fault.

<?
echo base64_decode('a3A');
echo base64_decode('MTBiZXQ');
?>

The strings are base64_encoded strings with the terminating = removed (hence they are not true base64-encoded strings).

The error has been reproduced on 3.0.12 as well as on 3.0.5.