Multimedia software firm Adobe advised all Mac OS X 10.6 users on Thursday to upgrade their Flash Player software, as installing the latest Apple OS reverts the ubiquitous Flash software to a vulnerable version.

In a post to its Product Security Incident Response Teams (PSIRT) blog, the Adobe security team warned that the Apple's Snow Leopard update, which shipped a week ago, would install a vulnerable version of the Flash Player software. Flash is commonly used on Web sites to add multimedia features and greater interactivity.

Security firm Sophos chided Apple for downgrading its users security.

"Mac users are not informed that Snow Leopard has downgraded their version of Flash without permission, and that they are now exposed to a raft of potential attacks and exploits which have been targeted on Adobe's software in recent months," Graham Cluley, senior technology consultant for the firm, said in a statement.

Apple's Snow Leopard update, which adds few obvious features but improves the Mac OS X's performance, has caused a few issues with security. Computers that have PGP's encryption and data-security software have to remove the program before installing the update, as there are conflicts between the programs.

Users of Snow Leopard, or any other operating system, that want to make sure they are running the latest version of Flash can go to Adobe's Web site.

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