Here I would like to bring your attention to the new security update for WSS3.0 and MOSS 2007 Microsoft Security Bulletin MS10-039 Vulnerabilities in Microsoft SharePoint Could Allow Elevation of Privilege (2028554).
For more details you may read here
http://support.microsoft.com/kb/979445 for MOSS and http://support.microsoft.com/kb/979444 for WSS3.0  .

The February 2010 CU http://blogs.msdn.com/b/ahmad_adainat/archive/2010/02/25/wss3.0-and-moss-2007-feb-2010-cumulative-update-is-now-ready.aspx  should have the fix as well, but just in case you don’t have regular update for your farm then installing the security update would do job.

[Update]
Please pay attention to this issue 
http://blogs.technet.com/b/sbs/archive/2010/06/18/companyweb-and-sharepoint-central-admin-not-accessible-after-installing-kb983444.aspx raised after installing the Security Fix in question on the SBS (Small Business Server).