Meta and Yandex have exploited a loophole in the Android operating system, allowing them to link web browsing data with app identities, bypassing privacy measures like incognito mode. This was revealed by researchers from the Local Mess project, who found that tracking scripts (Meta Pixel and Yandex Metrica) embedded in millions of websites transmit data from web browsers to apps such as Facebook, Instagram, and Yandex Maps through local network connections. Meta began using this technique in late 2024, while Yandex has been doing so since 2017. The loophole allows browser data to be sent to localhost, enabling apps to access it without user notification. In response, Meta has paused the feature and is working with Google to address the issue, which Google acknowledges violates Play Store policies. Some browsers are blocking this tracking, but researchers warn that solutions may be temporary without stricter restrictions on app access to local ports. The study indicates that most sites using these trackers start data collection immediately upon visiting, often before consent is requested. To prevent this tracking, users are advised to uninstall the affected applications.