FairEmail: Path traversal in shared attachment handling can write files outside the intended shared directory

FairEmail is a fully featured, open source, privacy-friendly email app for Android. Prior to 1.2325, shared attachment handling does not adequately sanitize an attacker-controlled filename before constructing its destination path. A local attacker-controlled app can therefore supply path components that escape the intended shared attachment directory and overwrite or corrupt files in the FairEmail private data directory, including account or message databases. Exploitation requires app lock using PIN or biometric authentication and user interaction to unlock FairEmail. This issue is fixed in version 1.2325.