On Wednesday, William Carrel posted an advisory warning of a malicious DHCP response that can grant root access for Mac OS X. The vulnerability affects the desktop and server versions of Mac OS X 10.2, known as Jaguar, as well as Mac OS X 10.3, known as Panther, he wrote.
Carrel noted that Apple Computer Inc. currently has no patch for the hole but may be looking to provide an update in December. Carrel wrote that he had notified Apple of the security issue before Panther and a November security update were released.
Apple officials could not be immediately reached for comment.
Separately, Copenhagen, Denmark-based security company Secunia issued a security advisory late Tuesday about five security vulnerabilities in Internet Explorer 6.0 and possibly in earlier versions of the browser as well. Together, they "can be exploited to compromise a users system" the advisory warns.
Secunia suggested that users disable "active scripting" or use another browser to avoid the vulnerabilities.
Microsoft officials said that they were investigating the issue but have not been made aware of any exploits or customer impacts of the reported vulnerabilities.
"Upon completion of this investigation, Microsoft will take the appropriate action to protect our customers, which may include providing a fix through our monthly patch release process or an out-of-cycle patch, depending on customer needs," said Stephen Toulouse, security program manager of Microsofts Security Response Center, in a statement.
In addition, Secunia late last week also found vulnerabilities in the Opera browser, Version 7.22 and earlier, that can cause a buffer overflow. Opera this week released an update to its browser, Opera 7.23, that fixes the holes.