Could an In-App Ad Infect My Outdated Android Phone?

If you only saw TikTok open and did not install an APK, grant permissions, or enter information, the chance that this single event infected the phone is fairly low. Keep Play Protect enabled, install all available system and app updates, and avoid downloading apps from outside the official app store. A factory reset is usually unnecessary unless you notice persistent pop-ups, unknown apps, account activity, or other symptoms. If the phone cannot be updated, replacing it with a supported model is the safest long-term option.

An ad opening TikTok does not by itself mean malware was installed. Ads can use links that launch another app, and a bad ad network can make that happen without a deliberate tap. Since this is repeatedly reported for the same app, I would stop using or uninstall it for now, report the behavior to the developer, and reinstall only if it gets fixed.

Android 11 being out of security support is the bigger long-term concern. Play Protect and a reputable built-in scanner coming back clean is reassuring, but scans cannot make an unsupported operating system fully safe. Check for unknown apps, unusual accessibility or device-administrator permissions, excessive battery or data use, and browser notification permissions. Remove anything unfamiliar and change important passwords from a trusted device if you find suspicious activity.