NanaZip is the 7-Zip derivative intended for the modern Windows experience. From version 3.0.1000.0 to before version 6.0.1698.0, a heap out-of-bounds read exists in the Android Verified Boot (AVB) vbmeta image parser in NanaZip (via the upstream 7-Zip AvbHandler). An unsigned integer underflow in a bounds check allows an attacker-controlled value_num_bytes field to pass validation, causing AddNameToString to read up to ~4 GiB past the end of a 64 KiB heap buffer. This causes a deterministic crash (denial of service) when opening a crafted .avb or .img file. This issue has been patched in stable version 6.0.1698.0 and preview version 6.5.1742.0.