Apple Patches macOS Screen Sharing Authentication Flaw; Update Your Mac
If you use a Mac, there is a security update worth installing rather than leaving it in the “I’ll get to that later” pile.
Apple has released macOS Tahoe 26.6.1, Sequoia 15.7.9 and Sonoma 14.8.9 to address a Screen Sharing authentication flaw. According to Apple’s release information cited by multiple reports, an attacker on the same network could potentially authenticate to Screen Sharing without valid credentials. Apple addressed the problem by changing how the authentication state is handled.
That “on the same network” qualification matters. This is not reporting that somebody anywhere on the internet can instantly take over every Mac. But shared networks are hardly exotic. Offices, schools, hotels, coworking spaces, apartment buildings and public Wi-Fi all create situations where devices you do not control may be sitting on the same local network as yours.
Screen Sharing is also exactly the sort of service where an authentication failure deserves attention. The whole point of the feature is remote access to a Mac’s screen. If the gatekeeper checking credentials can be bypassed, the consequences are potentially much more interesting than a bug that merely crashes an application.
There is no public indication in the reporting so far that this particular flaw was being actively exploited before the patch became available. That is good news, but it is not an argument for waiting. Once a security fix ships, attackers get another useful clue about where the underlying weakness lives.
For individuals, the action is simple: install the current macOS update offered for your supported version. For businesses managing Macs, make sure the update is actually reaching machines instead of assuming employees eventually click the button. If Screen Sharing or Remote Management is not needed on a system, there is also no benefit in leaving unnecessary remote-access services enabled.
This is not the most glamorous technology story of the week. It is, however, the kind that can matter a great deal to the person whose computer gets accessed. Security updates are boring right up until the moment they aren’t.
Sources
Tom’s Guide: macOS Screen Sharing security update
Golem: Screen Sharing vulnerability and patched macOS versions