The OS X 10.5.7 update includes 67 patches or fixes, including a severe security problem in the browser which could pave the way for cross-site scripting attacks when visiting a site through an Apache-based proxy.
Others apply a plaster to Safari and CoreGraphics issues.
Elsewhere, a problem with iChat that might have given an attacker access to AOL instant messaging conversations has been resolved, as have numerous issues with the Adobe Flash Player plug-in.
OpenSSL has also been targeted. Apple warned that "a man-in-the-middle attacker may be able to impersonate a trusted server or user in applications using OpenSSL for SSL certificate verification" unless the patch is applied.
New hardware support has been added to the operating system, along with improvements to a number of Apple's desktop widgets such as the weather application.
Improvements when running third-party applications such as Yahoo or Gmail have also been made, while support for networking has been boosted.
The update is recommended for all users running Mac OS X Leopard. It can be downloaded automatically depending on the user's set-up.