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Did a Terrible Android App Flaw Just Expose Your Nextcloud Files to Your Boss?
A bug in the Nextcloud Android app could be a serious data protection issue for some users. The problem causes media files, like photos and videos, to be uploaded to multiple accounts without permission, even when the auto-upload feature is turned off for those accounts. This can lead to private files being copied to a work server or other shared environments unintentionally.
Understanding Nextcloud
Nextcloud is a special kind of software that lets you build your own private cloud. Think of it like Google Drive or Dropbox, but instead of your files living on a server owned by a big company, they live on a server that you control. This server can be in your home, at your office, or hosted by a provider you trust. The main idea behind Nextcloud is to give you full control over your data. You decide where it is stored and who gets to see it.
People use it to store all sorts of things, such as documents, photos, calendars, and contacts. You can access your files from a web browser on a computer or through an app on your phone. This makes it easy to have all your important information in one central place, accessible from any of your devices. Nextcloud also allows you to share files with other people and includes tools for video calls and online document editing.
The Android app is a key part of the Nextcloud experience. It connects your phone to your personal cloud server. Through the app, you can look at your files, download them to your phone, or upload new ones. One of the most popular features is the automatic upload for photos and videos. When you turn this on, any new picture you take with your phone’s camera is automatically sent to your Nextcloud server. This creates a backup and makes your photos available on your other devices. The app is also designed to handle more than one Nextcloud account at the same time, which is where the recent problem begins.
A Critical Auto-Upload Bug
A user of the Nextcloud Android app recently discovered a significant bug. This flaw affects users who have a specific setup on their phone. For the bug to appear, two conditions must be met:
- You must be signed into more than one Nextcloud account within the Android app. For example, you might have one account for your personal files and another for your work files.
- You must have the “automatic upload” feature for photos and videos turned on for at least one of those accounts.
When these conditions are met, the app is supposed to upload new photos only to the account where you enabled the feature. However, the bug in version 3.32.3 of the Android app causes something very different to happen. The app correctly uploads the new photos and videos to the intended folder in your primary Nextcloud account. The problem is that it does not stop there. It also creates a new folder in all other Nextcloud accounts you are signed into and uploads a copy of every single one of those files there, too. This happens even if automatic uploads are completely disabled for those other accounts.
Imagine you have a personal Nextcloud for your family photos and a work Nextcloud provided by your employer. You turn on auto-upload for your personal account to back up your vacation pictures. Due to this bug, the app would not only send those pictures to your private server but would also copy them onto your company’s server. This creates a serious privacy breach, as your personal files are now in a professional environment without your knowledge or consent. This is particularly concerning because the very purpose of having separate accounts is to keep personal and professional data strictly segregated.
The Impact on Your Privacy
This bug is more than just a minor inconvenience; it is a major data protection risk. The accidental mixing of personal and professional data can lead to serious consequences. If personal photos are uploaded to a work server, they could be seen by IT administrators, supervisors, or even colleagues who have access to that system. This could result in personal embarrassment or a violation of your company’s data policies, which often forbid storing personal files on company resources.
The issue strikes at the heart of why many people choose Nextcloud in the first place: privacy and control. Users trust the platform to keep their data secure and separate. A bug like this breaks that trust. It performs actions that the user explicitly did not authorize, sending sensitive information to unintended locations. The fact that it happens silently in the background makes it even more dangerous, as a user might not notice the breach for a long time.
What to Do Now
The bug was reported by a user to the Nextcloud development team on GitHub in early September 2025. The developers quickly acknowledged the problem and have been working on a solution. The issue has been marked as “closed,” which indicates that a fix has been developed and should be included in the next update to the Android app. While a fix is on the way, it will not delete any files that have already been copied incorrectly. You must take action to protect your information now.
Disable Auto-Upload Immediately
If you use multiple Nextcloud accounts on your Android device, open the app and turn off the automatic upload feature for all accounts right away. This is the most important step to prevent any more of your files from being copied.
Check All Your Accounts
Carefully inspect the file directories of all your Nextcloud accounts, especially any work or shared accounts. Look for a new folder that contains photos and videos from your phone. These are the files that were uploaded by the bug.
Delete the Unwanted Files
Once you find any files that were copied to the wrong account, delete them permanently from that server. This is the only way to ensure your private data is removed from the unintended location.
Update Your App
Keep an eye out for a new update for the Nextcloud app in the Google Play Store. Install it as soon as it becomes available. The release notes for the new version should mention a fix for the auto-upload bug.
This situation serves as a critical reminder about digital hygiene. Always be mindful of the permissions you grant to applications, and regularly check to ensure your data is being handled as you expect. Even with trusted, privacy-focused software, errors can occur, and staying vigilant is your best defense.