Untrusted search path vulnerability in avast! Free Antivirus version 5.0.594 and earlier allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse mfc90loc.dll that is located in the same folder as an avast license (.avastlic) file.

Aavmker4.sys in avast! 4.8 through 4.8.1368.0 and 5.0 before 5.0.418.0 running on Windows 2000 and XP does not properly validate input to IOCTL 0xb2d60030, which allows local users to cause a denial of service (system crash) or execute arbitrary code to gain privileges via IOCTL requests using crafted kernel addresses that trigger memory corruption.

Heap-based buffer overflow in aswRdr.sys (aka the TDI RDR driver) in avast! Home and Professional 4.8.1356.0 allows local users to cause a denial of service (memory corruption) or possibly gain privileges via crafted arguments to IOCTL 0x80002024.

Stack-based buffer overflow in aswMon2.sys in avast! Home and Professional for Windows 4.8.1351, and possibly other versions before 4.8.1356, allows local users to cause a denial of service (system crash) and possibly gain privileges via a crafted IOCTL request to IOCTL 0xb2c80018.

aavmKer4.sys in avast! Home and Professional for Windows before 4.8.1356 does not properly validate input to IOCTLs (1) 0xb2d6000c and (2) 0xb2d60034, which allows local users to gain privileges via IOCTL requests using crafted kernel addresses that trigger memory corruption, a different vulnerability than CVE-2008-1625.

Unspecified vulnerability in ashWsFtr.dll in avast! Home and Professional for Windows before 4.8.1356 has unknown impact and local attack vectors.

Multiple stack-based buffer overflows in avast! Linux Home Edition 1.0.5, 1.0.5-1, and 1.0.8 allow remote attackers to cause a denial of service (application crash) or execute arbitrary code via a malformed (1) ISO or (2) RPM file.

avast! antivirus 4.8.1281.0, when Internet Explorer 6 or 7 is used, allows remote attackers to bypass detection of malware in an HTML document by placing an MZ header (aka "EXE info") at the beginning, and modifying the filename to have (1) no extension, (2) a .txt extension, or (3) a .jpg extension, as demonstrated by a document containing a CVE-2006-5745 exploit.

aavmker4.sys in avast! Home and Professional 4.7 for Windows does not properly validate input to IOCTL 0xb2d60030, which allows local users to gain privileges via certain IOCTL requests.

Unspecified vulnerability in avast! 4 Home and Professional Editions before 4.7.1098 allows remote attackers to have an unknown impact via a crafted TAR archive.