Flatpak 1.19.1 prerelease addresses multiple security vulnerabilities

The Flatpak 1.19.1 development prerelease introduces critical security fixes to prevent malicious applications from overwriting or deleting privileged files. It also addresses vulnerabilities involving OCI repository authentication tokens and potential denial of service attacks targeting the desktop environment. Additionally, the release includes build system changes and several bug fixes for the system helper and sandbox functionality.

Security and technical improvements in 1.19.1

• Security fixes: Patches CVE-2026-97024 and CVE-2026-97023 to prevent privileged file overwrites and deletions via symlinks or empty files.
• Authentication security: Prevents authentication tokens from being visible to other users when downloading from OCI repositories (CVE-2026-97025).
• DoS prevention: Implements field allowlisting for .desktop and D-Bus .service files (CVE-2026-97027) and restricts apps from signaling parent processes outside the sandbox (CVE-2026-97029).
• Build system: Migrates libglnx and variant-schema-compiler from git subtrees to Meson wrap subprojects.
• New API: Adds flatpak_user_data_delete() to allow management UIs to implement data deletion during uninstallation.

Why it matters

This release hardens the sandbox environment against malicious applications attempting to escape or disrupt the host system.