Mac OS X v10.5.6 update includes a critical update for Adobe Systems’ Flash Player. It also includes patches for several Mac OS libraries, the operating system kernel, and system utilities. In total, 21 bugs are patched in the update, fixing a number of critical flaws in the software. The timing of Apple’s patches is noteworthy because cybercriminals often like to launch attacks in December, when IT staff are on vacation and computer emergency response teams are often slower to respond to threats.”]
Source: https://www.csoonline.com/article/2123489/apple–critical-mac-os-x-security-patches.html