zbar: zbar: heap-buffer-overflow write in Structured-Append QR text extraction

A flaw was found in the ZBar barcode reader library. A heap-buffer-overflow write of one byte occurs when processing Structured-Append QR codes where the buffer size calculation does not account for NUL separator bytes inserted between decoded segments. An attacker could exploit this by crafting a QR code image that, when scanned by an application using zbar, causes heap corruption leading to a denial of service (application crash).