An issue was discovered in ClamXAV 3 before 3.1.1. A malicious actor could use a properly signed copy of ClamXAV 2 (running with an injected malicious dylib) to communicate with ClamXAV 3's helper tool and perform privileged operations. This occurs because of inadequate client verification in the helper tool.

freshclam in (1) Clam Antivirus (ClamAV) 0.88 and (2) ClamXav 1.0.3h and earlier does not drop privileges before processing the config-file command line option, which allows local users to read portions of arbitrary files when an error message displays the first line of the target file.