The latest version of the Mac OS X operating system includes Adobe's Flash Player, but it is not the latest patched version.
Mac users who update to version 10.6.4 of the operating system should ensure their Flash Player is updated to version 10.1.53.64, said Brad Arkin, director, product security and privacy at Adobe Systems.
However, Mac OS 10.6.4 does not appear to downgrade users who have previously updated to Flash Player 10.1.53.64, so there is no need for them to reapply the update, he said.
Adobe confirmed that criminals have been exploiting the flaw using malicious Flash swf files, which are typically opened by the Web browser's Flash Player plugin, or through PDFs that have maliciously encoded Flash components embedded inside them.
Those malicious PDFs are typically opened by Reader or Acrobat, which include their own versions of Flash Player, due to be patched on 29 June.
The updated software from Adobe fixes 32 vulnerabilties, but it is still unclear when a similar update will be issued for Flash Player on Solaris.
Adobe's Flash and Reader software have become prime hacking targets in the past year because of the software's large install base.
The company is considering increasing the frequency of security updates along the same lines as Microsoft's monthly Patch Tuesday, Arkin has said in recent weeks.