Off-by-one buffer overflow in pnmtopng before 2.39, when using the -alpha command line option (Alphas_Of_Color), allows attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted PNM file with exactly 256 colors.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.