Apple late Thursday issued a megapatch that fixes 25 security vulnerabilities on its Mac OS X desktop and OS X server systems.

Twelve of the vulnerabilities being patched would enable remote code execution, which is generally considered to be a "critical" bug in security circles. Several other bugs enable users to advance their system privileges without authorization.

The patches come in a download identified as Security Update 2007-004.

Some of the bugs being patched were first publicly disclosed during the Month of Apple Bugs project in January.

This round of patches comes a month after Apple issued a massive security update that fixed 45 flaws, including several zero-day bugs.

One patch tends to elevated privilege issues in Apple's AirPort, which is its wireless technology. Another bug is fixed in Help Viewer that could lead to an application shutdown or arbitrary code execution. A similar flaw in Installer also is patched. IChat, Apple's videoconferencing and instant messaging application, also keeps an update, as well.

A critical flaw also is patched in Libinfo, which is a code library used in Mac OS X. In the security advisory, Apple explains that Libinfo does not correctly report errors to applications that use it. By luring a user to visit a malicious Web page, a hacker can gain access to the system and execute code remotely. Apple's latest patch also deals with a vulnerability in its Kerberos authentication system. An uninitialized function pointer bug sits in the MIT Kerberos administration daemon (kadmind), which could cause an unexpected application termination or arbitrary code execution with system privileges.

The security update can be manually downloaded from Apple's Security Web site.