Long filename extensions can cause endless loop
Files received by PostMaster or by upload that have very long filename extensions can cause an endless loop in OTRS.
Upgrade to the latest available OTRS patch level (https://ftp.otrs.org/pub/otrs/).
As a workaround, you can replace the affected files (see below for download).
ATTENTION: Please check if any of these files have been changed in your OTRS installation by additional add-ons. In that case you MUST NOT simply overwrite the files with the ones provided below. Please contact us instead.