It doesn't hang, the plug-in just plain crashes.

Could be a duplicate of bug #163256.

It may partly be a duplicate, but there is more to it:  the DICOM plug-in has
some limitations.  For example, the DICOM standard does not actually require a
valid DICOM file to have a DICOM header (and some of the examples on the
referenced site do not), but the DICOM plug-in will fail for files that don't.

DICOM is imho the nastiest file format of all to code for -- the file format
specs look like they were written by lawyers.

Let's remove the plug-in from the GIMP distribution then and hand over
maintainance to someone who is capable and willing to spend his/her free time
with this nasty beast.

Common, but it's commonly used in medical imaging. Thre are gigabytes of these
on the internet.
ImageMagic supports it no problem.
Whole purpose of image format plugins is to accomodate such beasts under common
roof.

I didn't say it should be banned. But it appears that we don't have anyone in
the GIMP development team who wants to work on this. Moving it out of the tree
might be a big step forward for the plug-in. Of course we would first have to
find a maintainer. Are you volunteering?

Let's try to say this a little bit less aggressively.  DICOM is a difficult
enough format that it almost requires a medical imaging specialist to maintain
the plug-in, and none of the current active GIMP developers is one.  If you know
somebody who has a good understanding of the DICOM format and is willing to do
it, it would be very helpful.  Since this is a plug-in, only minimal knowledge
of GIMP internals would be required.

Both this bug and bug #163256 are about problems with the DICOM plug-in, and
although there is undoubtedly more than one problem, it makes most sense at this
point to consolidate them.  Bug #163256 contains more useful information, so I
will mark this one as a duplicate.

*** This bug has been marked as a duplicate of 163256 ***