A missing bound check in RTCP flag parsing code prior to WhatsApp for Android v2.21.23.2, WhatsApp Business for Android v2.21.23.2, WhatsApp for iOS v2.21.230.6, WhatsApp Business for iOS 2.21.230.7, and WhatsApp Desktop v2.2145.0 could have allowed an out-of-bounds heap read if a user sent a malformed RTCP packet during an established call.