SIGABRT at poppler/Object.h:258

As of de0c0b83, when invoking pdfunite TESTPDF POC OUTPUT.pdf, it may crash with the following backtrace:

Program received signal SIGABRT, Aborted.
__GI_raise (sig=sig@entry=0x6) at ../sysdeps/unix/sysv/linux/raise.c:51
51      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
#0  __GI_raise (sig=sig@entry=0x6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007ffff5f3a801 in __GI_abort () at abort.c:79
#2  0x000000000051e117 in Object::getDict (this=0x7fffffffbd70) at ../poppler/Object.h:258
#3  main (argc=<optimized out>, argv=<optimized out>) at ../utils/pdfunite.cc:205

pdfunite.zip

2 POCs are attached inside the zip file; TESTPDF seems not important.