libclamav in ClamAV (aka Clam AntiVirus), as used in Advanced Malware Protection (AMP) on Cisco Email Security Appliance (ESA) devices before 9.7.0-125 and Web Security Appliance (WSA) devices before 9.0.1-135 and 9.1.x before 9.1.1-041, allows remote attackers to cause a denial of service (AMP process restart) via a crafted document, aka Bug IDs CSCuv78533 and CSCuw60503.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.