A buffer underwrite (buffer underflow) vulnerability in the administrative interface of Fortinet FortiOS version 7.2.0 through 7.2.3, version 7.0.0 through 7.0.6, version 6.4.0 through 6.4.11 and version 6.2.12 and below, FortiProxy version 7.2.0 through 7.2.2, version 7.0.0 through 7.0.8, version 2.0.12 and below and FortiOS-6K7K version 7.0.5, version 6.4.0 through 6.4.10 and version 6.2.0 through 6.2.10 and below allows a remote unauthenticated attacker to execute arbitrary code or commands via specifically crafted requests.
The product writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer.