A vulnerability in the ClamD service module of Clam AntiVirus (ClamAV) versions 1.4.0, 1.3.2 and prior versions, all 1.2.x versions, 1.0.6 and prior versions, all 0.105.x versions, all 0.104.x versions, and 0.103.11 and all prior versions could allow an authenticated, local attacker to corrupt critical system files. The vulnerability is due to allowing the ClamD process to write to its log file while privileged without checking if the logfile has been replaced with a symbolic link. An attacker could exploit this vulnerability if they replace the ClamD log file with a symlink to a critical system file and then find a way to restart the ClamD process. An exploit could allow the attacker to corrupt a critical system file by appending ClamD log messages after restart.