Adobe Systems fixed 13 security issues in Flash Player that could lead to serious attacks, including remote code execution and information disclosure.
Users should upgrade to Flash Player 18.104.22.168 for Windows and Mac, Adobe Flash Player 22.214.171.1246 for Linux, or Flash Player 126.96.36.1992 if they are on the extended support release channel.
Users of Internet Explorer on Windows 8.x and Google Chrome on Windows, Linux and Mac will receive the Flash Player update for their respective browser automatically.
Adobe also released updates for the AIR runtime on Windows, Mac and Android, as well AIR SDK and Compiler, because these programs bundle Flash Player.
Six of the new vulnerabilities patched in Flash Player could be exploited to achieve remote code execution. These are the kind of vulnerabilities used in drive-by download attacks launched through compromised websites or malicious ads to install malware on users' computers.
Adobe is not aware that any of the newly-patched vulnerabilities are being actively exploited by attackers. However, history has shown that attackers are quick to target new Flash flaws after a fix becomes available for them. Earlier this year, attackers started exploiting a Flash Player vulnerability just one week after Adobe released a patch for it.
The new Flash updates also fix four vulnerabilities that can be exploited to bypass the same-origin policy, a critical security mechanism in browsers that prevents code running on a website from accessing the content of other websites opened in the same browser. Without it, a rogue website could, for example, harvest the emails of users who have Gmail opened in another tab.
On Tuesday, Adobe again tried to patch a flaw it partially fixed twice before. That fix is for a publicly disclosed attack called the Rosetta Flash for which proof-of-concept exploits exist.
The remaining fixes in the new Flash Player updates address a flaw that can be used to bypass an OS anti-exploitation mechanism called the address space layout randomization (ASLR) and one that can be used to escalate the privilege of the Flash Player broker in Internet Explorer from low to medium integrity level.