The ignore_section_sym function in elf.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.30, does not validate the output_section pointer in the case of a symtab entry with a "SECTION" type that has a "0" value, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted file, as demonstrated by objcopy.