The Tasks.org Android app uses the activity ShareLinkActivity.kt to handle "share" intents coming from other components in the same device and convert them to tasks. Those intents may contain arbitrary file paths as attachments, in which case the files pointed by those paths are copied in the app's external storage directory. Prior to versions 12.7.1 and 13.0.1, those paths were not validated, allowing a malicious or compromised application in the same device to force Tasks.org to copy files from its internal storage to its external storage directory, where they became accessible to any component with permission to read the external storage.

Impact

This vulnerability can lead to sensitive information disclosure. All information in the user's notes and the app's preferences, including the encrypted credentials of CalDav integrations if enabled, could be accessed by third party applications installed on the same device.

Patches

This issue was fixed in versions 12.7.1 and 13.0.1.

Workarounds

There are no known workarounds.

References

Fix commit: 23bf69d

For more information

If you have any questions or comments about this advisory:

• Open an issue in github.com/tasks/tasks
• Email us at support@tasks.org