Apple has turned off group Facetime calls for all of its users following the discovery of a serious security flaw in the voice and video chatting service. The company plans to roll out a proper software fix for the issue later this week.

Apple took the unusual step to remotely disable parts of Facetime after reports surfaced Monday afternoon that users could access other people’s iPhone microphones and cameras without their knowledge.

The flaw, which was likely introduced with a software update last December, allowed a caller to listen in on a phone even before the owner of that phone had picked up. What’s more, users who dismissed a call could inadvertently give callers access to their phones’ front-facing cameras.

Spying on users this way involved making use of Apple’s group Facetime functionality, which is why the company pulled the plug on that feature Monday night. Apple disclosed the unusual step via its system status page, simply stating that group Facetime was “temporarily unavailable.”

News of the serious security flaw broke just before Apple’s latest quarterly earnings report, which the company is set to deliver Tuesday after market close. The timing isn’t ideal for the company: Investors are already worried about Apple’s performance after it disclosed earlier this month that it had underestimated the challenges to its China business.