Gthumb crashes when trying to open files exported by Darktable

Status changed to 'Confirmed' because the bug affects multiple users.

It also happens in gwenview for a file exported from Darktable... same error.

$gwenview FXT21038_0.jpg
org.kde.kdegraphics.gwenview.lib: Unresolved mime type "image/x-mng"
org.kde.kdegraphics.gwenview.lib: Unresolved raw mime type "image/x-nikon-nrw"
org.kde.kdegraphics.gwenview.lib: Unresolved raw mime type "image/x-samsung-srw"
terminate called after throwing an instance of 'std::out_of_range'
  what(): basic_string::at: __n (which is 19) >= this->size() (which is 19)
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = gwenview path = /usr/bin pid = 24875
KCrash: Arguments: /usr/bin/gwenview FXT21038_0.jpg
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi

[1]+ Aturat gwenview FXT21038_0.jpg

5.11.0-37-generic #41-Ubuntu SMP
kubunut 21.04

I upgraded from Ubuntu 21.04 to 21.10 and the bug is still present.
On the mageia distribution they seem to have fixed the bug that would come from lib64exiv2:
https://bugs.mageia.org/show_bug.cgi?id=29440

The crash is in Gthumb and gwenview

I was having the same issue in Kubuntu 20.04. The issue went away after I downgraded libexiv2 from version 0.27.2-8ubuntu2.6 to version 0.27.2-8ubuntu2 as follows:

sudo apt-get install libexiv2-27=0.27.2-8ubuntu2

Will this be fixed in this century? I slowly moved from Ubuntu 20.04 to 21.10. And in all of those versions, issue persisted. Some time ago I could just downgrade the version of libexiv2. Now the previous version is no longer accessible from repo. I can not use my favorite image viewer, Gthumb. It just crashes on all of my photos exported from Darktable.

The issue is around libexiv2.

How I solve it:
I rename (yes, desperate try) the library libexiv2.so.0.27.3 to undo the symbolic link and recover the lib if this try fails -or other program crashes-.

In my Ubuntu the library is placed at: /usr/lib/x86_64-linux-gnu

It works for my Ubuntu 21.10 with gThumb 3.11.2 installed from Ubuntu.
I reinstall gThumb to "repeat" the process: gThumb redo the symbolic link and crashes again, I undo the symbolic link and it works.

Other applications are working fine after (Darktable of course, Shotwell, etc.) nothing weirdz detected.

I expect that it works for you.

Upstream claims it's fixed in libexiv2 v0.27.5: https://github.com/Exiv2/exiv2/issues/2011

I confirm it, right now I was checking it (https://www.exiv2.org/) Thank you Ben!