this bug is triggered through qmailadmins adddotqmailnow command: if there are no .qmail files beside .qmail-default (i.e. there are no lists or aliases yet), during its first run valias_select_names leaves num_names at 0 but still does a realloc, since num_names is 0 and therefore smaller than max_names. this results in realloc(names, 0) being called, which is the same as calling free(names)...
2009-07-09 07:44:35 UTC in vpopmail - virtual domains for qmail