The findcolororerror function in gifsicle 1.92 contains a NULL pointer dereference.

A double-free bug in the readgif function in gifread.c in gifsicle 1.90 allows a remote attacker to cause a denial-of-service attack or unspecified other impact via a maliciously crafted file, because lastname is mishandled, a different vulnerability than CVE-2017-1000421.

Gifsicle gifview 1.89 and older is vulnerable to a use-after-free in the readgif function resulting potential code execution