How to repair a serialized string which has been corrupted by an incorrect byte count length?

Question

I am using Hotaru CMS with the Image Upload plugin, I get this error if I try to attach an image to a post, otherwise there is no error:

unserialize()

Answer 1

the official docs says it should return false and set E_NOTICE

but since you got error then the error reporting is set to be triggered by E_NOTICE

here is a fix to allow you detect false returned by unserialize

$old_err=error_reporting(); 
error_reporting($old_err & ~E_NOTICE);
$object = unserialize($serialized_data);
error_reporting($old_err);

you might want to consider use base64 encode/decode

$string=base64_encode(serialize($obj));
unserialize(base64_decode($string));