Lotus is to rush out a security patch for Notes 4.6 client "within a month" after a leading independent lab published details of a security loophole in the software on the internet. Lotus officials played down the likelihood of the flaw being exploited, but said that it would be addressed in the Notes Release 5 upgrade, and in an interim patch. The patch, Notes 4.6 2A, will be available on the Lotus Web site. According to L0pht Heavy Industries, the Notes 4.6 client loophole is caused by a feature in the software that allows developers to preview Domino-based applications. In tests, L0pht claimed that hackers could misuse the preview feature to get unauthorised access to data. L0pht said that the loophole particularly affected sites that were using Notes as a development platform or as an intranet. Affected users, according to L0pht, are advised to manually edit the access control lists, and to set up routing filters to prevent access to the HTTP port of Notes client-only machines. L0pht, which comes out of a US hacking group, has previously listed a number of other security flaws in Lotus Notes, including the ability of Web users to write to remote server drives and change server configuration files.