ZBar commit 2ea2ca58 contains an undefined-behavior vulnerability in the Code 128 decode6() function. When processing specially crafted Code 128 input, decode_e() can return -1 for an invalid edge pattern, and decode6() subsequently left-shifts this negative signed value while constructing the edge signature. The operation invokes undefined behavior and can terminate trap-mode UBSan builds with SIGILL, resulting in denial of service.