Each eCryptfs file has metadata associated with it that is normally stored in the header of the file. The metadata is stored in "packet" form according to RFC 2440 "OpenPGP Message Format". Each packet has a header section itself, which has fields such as the packet length. When reading the packet contents, the packet length field is used for the memcpy to the destination buffer but is not checked against the size of the destination buffer. This could result in a buffer overflow if a malicious user hand-modifies the packet length field.