In mid-September, Apple was forced to issue an emergency security update for its iPhone, iPad, Mac, and Watch operating systems after being alerted to a “no click” exploit allegedly tied to the Pegasus surveillance software distributed by the Israeli company NSO Group.

The Citizen Lab, a Canadian human rights and security advocacy group, alerted Apple to the exploit, dubbed FORCEDENTRY. The exploit targeted Apple’s image rendering library, which was found on the phone of a Saudi activist that Citizen Lab examined back in March. The exploit uses “maliciously crafted” PDF files that could lead to “arbitrary code execution,” Apple said in a security bulletin.