Using desktop-file-validate on the attached file will cause an out of bounds memory read. This can be seen by compiling with address sanitizer (CFLAGS="-fsanitize=address") or with valgrind.

Here's the content of the file:
[Desktop Entry]
Exec=\

Seems the parsing of the backslash doesn't consider the case when the line or file ends.

This is the relevant part of the output of address sanitizer:
==3905==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000ee92 at pc 0x0000004ea227 bp 0x7ffd88d0cc50 sp 0x7ffd88d0cc48
READ of size 1 at 0x60200000ee92 thread T0
    #0 0x4ea226 in handle_exec_key /mnt/ram/desktop-file-utils-0.22/src/validate.c:1229:10
    #1 0x4e4c06 in handle_desktop_exec_key /mnt/ram/desktop-file-utils-0.22/src/validate.c:1397:10
    #2 0x4ed190 in validate_known_key /mnt/ram/desktop-file-utils-0.22/src/validate.c:2248:12
    #3 0x4ec80c in validate_action_key /mnt/ram/desktop-file-utils-0.22/src/validate.c:2284:10
    #4 0x4ec80c in validate_keys_for_current_group /mnt/ram/desktop-file-utils-0.22/src/validate.c:2376
    #5 0x4e19cb in validate_flush_parse_buffer /mnt/ram/desktop-file-utils-0.22/src/validate.c:2945:5
    #6 0x4e19cb in validate_parse_from_fd /mnt/ram/desktop-file-utils-0.22/src/validate.c:2993
    #7 0x4e19cb in validate_load_and_parse /mnt/ram/desktop-file-utils-0.22/src/validate.c:3011
    #8 0x4e19cb in desktop_file_validate /mnt/ram/desktop-file-utils-0.22/src/validate.c:3078
    #9 0x4ee9da in main /mnt/ram/desktop-file-utils-0.22/src/validator.c:81:17
    #10 0x7ff2f5906f9f in __libc_start_main (/lib64/libc.so.6+0x1ff9f)
    #11 0x4379d6 in _start (/mnt/ram/desktop-file-utils-0.22/src/desktop-file-validate+0x4379d6)

I'll attach the full output. This issue was found with the fuzzing tool american fuzzy lop.