AVM FRITZ!OS before 6.30 extracts the contents of firmware updates before verifying their cryptographic signature, which allows remote attackers to create symlinks or overwrite critical files, and consequently execute arbitrary code, via a crafted firmware image.
Weaknesses in this category are related to the design and implementation of data confidentiality and integrity. Frequently these deal with the use of encoding techniques, encryption libraries, and hashing algorithms. The weaknesses in this category could lead to a degradation of the quality data if they are not addressed.