Unverified indexs into the array lead to out of bound access in the gifoutcode function in fromgif.c in libsixel 1.8.6.

In libsixel 1.8.6, sixelencoderoutputwithoutmacro (called from sixelencoderencodeframe in encoder.c) has a double free.

Buffer Overflow in the "sixelencoderencodebytes" function of Libsixel v1.8.6 allows attackers to cause a Denial of Service (DoS).

loadpng in loader.c in libsixel.a in libsixel 1.8.6 has an uninitialized pointer leading to an invalid call to free, which can cause a denial of service.

libsixel 1.8.6 suffers from a Heap Use After Free vulnerability in in libsixel/src/dither.c:388.

libsixel 1.8.6 is affected by Buffer Overflow in libsixel/src/quant.c:876.

There is an assertion failure error in stbijpeghuffdecode, stbimage.h:1894 in libsixel img2sixel 1.8.6. Remote attackers could leverage this vulnerability to cause a denial-of-service via a crafted JPEG file.

There is a floating point exception error in sixelencoderdoresize, encoder.c:633 in libsixel img2sixel 1.8.6. Remote attackers could leverage this vulnerability to cause a denial-of-service via a crafted JPEG file.