The Pentagon has issued an urgent warning regarding the Signal messaging app, citing security flaws exploited by Russian hackers. This alert follows a significant breach where Trump administration officials mistakenly included a journalist in a classified chat about military operations. The Pentagon highlights concerns over phishing attacks that can lead to unauthorized access to sensitive conversations. Signal's representatives clarified that the app's security is sound but users must be cautious about linking unfamiliar devices. Experts advise vigilance against dubious links to prevent potential phishing scams.