unrar.c in libclamav in ClamAV before 0.90.3 and 0.91 before 0.91rc1 allows remote attackers to cause a denial of service (core dump) via a crafted RAR file with a modified vm_codesize value, which triggers a heap-based buffer overflow.

Integer signedness error in the (1) cab_unstore and (2) cab_extract functions in libclamav/cab.c in Clam AntiVirus (ClamAV) before 0.90.2 allow remote attackers to execute arbitrary code via a crafted CHM file that contains a negative integer, which passes a signed comparison and leads to a stack-based buffer overflow.

Gibraltar Firewall 2.2 and earlier, when using the ClamAV update to 0.81 for Squid, uses a defunct ClamAV method to scan memory for viruses, which does not return an error code and prevents viruses from being detected.