NanaZip is an open source file archive. From 5.0.1252.0 to before 6.0.1698.0, a one-byte heap out-of-bounds null write exists in the UFS/UFS2 filesystem image parser in NanaZip. The vulnerability is triggered when opening a crafted UFS filesystem image. The attacker controls the byte offset of the write within a ~254-byte window past the heap allocation boundary. This vulnerability is fixed in 6.0.1698.0.