Multiple interpretation error in unspecified versions of Grisoft AVG Antivirus allows remote attackers to bypass virus detection via a malicious executable in a specially crafted RAR file with malformed central and local headers, which can still be opened by products such as Winrar and PowerZip, even though they are rejected as corrupted by Winzip and BitZipper.

Multiple interpretation error in AVG 7 7.0.323 allows remote attackers to bypass virus scanning via a file such as BAT, HTML, and EML with an "MZ" magic byte sequence which is normally associated with EXE, which causes the file to be treated as a safe type that could still be executed as a dangerous file type by applications on the end system, as demonstrated by a "triple headed" program that contains EXE, EML, and HTML content, aka the "magic byte bug."

Grisoft AVG Free 7.1, and other versions including 7.0.308, sets Everyone/Full Control permissions for certain update files including (1) upd_vers.cfg, (2) incavi.avm, and (3) unspecified drivers, which might allow local users to gain privileges.