Firefox crashes with error "Inconsistency detected by ld.so"

I am using Ubuntu 16.04 LTS with gnome. From yetserday onwards firefox crashes with the following error:

• Inconsistency detected by ld.so: ../sysdeps/x86_64/dl-machine.h: 517: elf_machine_rela_relative: Assertion `ELFW(R_TYPE) (reloc->r_info) == R_X86_64_RELATIVE' failed!

  adwaita@adwaita-multiverse:~$ firefox
  
  (firefox:12320): Gtk-WARNING **: Theme parsing error: gtk.css:3218:17: The 'icon-shadow' property has been renamed to '-gtk-icon-shadow'
  
  (firefox:12320): Gtk-WARNING **: Theme parsing error: gtk.css:6378:23: The '-gtk-image-effect' property has been renamed to '-gtk-icon-effect'
  
  (firefox:12320): Gtk-WARNING **: Theme parsing error: gtk.css:6388:15: The 'icon-shadow' property has been renamed to '-gtk-icon-shadow'
  
  (firefox:12320): Gtk-WARNING **: Theme parsing error: gtk.css:6438:13: The 'icon-shadow' property has been renamed to '-gtk-icon-shadow'
  
  (firefox:12320): Gtk-WARNING **: Theme parsing error: gtk.css:6551:16: The 'outline-radius' property has been renamed to '-gtk-outline-radius'
  
  (firefox:12320): Gtk-WARNING **: Theme parsing error: gtk.css:6574:52: The :prelight pseudo-class is deprecated. Use :hover instead.
  Inconsistency detected by ld.so: ../sysdeps/x86_64/dl-machine.h: 517: elf_machine_rela_relative: Assertion `ELFW(R_TYPE) (reloc->r_info) == R_X86_64_RELATIVE' failed!
  adwaita@adwaita-multiverse:~$ 
  adwaita@adwaita-multiverse:~$ firefox --version
  Mozilla Firefox 49.0.2
  adwaita@adwaita-multiverse:~$