WASHINGTON, Aug 29 (Reuters) - WhatsApp said Friday it

discovered an advanced cyberespionage effort that took advantage

of a chain of security vulnerabilities in the app and Apple ( AAPL )

devices to hack them.

A researcher with Amnesty International said unidentified

members of civic groups appeared to be among those impacted.

In a brief statement, the Meta Platforms ( META )-owned

communications service said it had patched the security

vulnerability that allowed hackers to take advantage of a second

vulnerability on Apple ( AAPL ) devices and hijack the machines.

In a statement, WhatsApp said that fewer than 200 users

worldwide had potentially been impacted.

Donncha O Cearbhaill, who heads Amnesty's Security Lab, told

Reuters that his group was starting to collect forensic data

from potential victims.

In a post on X, he said that initial signs were that the

hacking "was impacting both iPhone and Android users, civil

society individuals among them." He said other apps beyond

WhatsApp may also have been affected.