Flatpak EUVD-2026-19971

Flatpak versions prior to 1.16.4 on Linux systems. Attacker must be able to run a Flatpak application; the vulnerable ld.so caching mechanism allows the sandboxed app to delete arbitrary host files by manipulating cache paths. No user interaction required.

This vulnerability presents moderate to high real-world risk despite the 8.7 CVSS score. The CVSS 4.0 vector indicates network-accessible attack (AV:N), low complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N), suggesting ease of exploitation. However, the impact is limited to high availability impact (VA:H) with no confidentiality or integrity impacts on the vulnerable system itself, which aligns with the file deletion capability. The actual risk is elevated because arbitrary file deletion on the host system from a sandboxed application represents a complete sandbox escape for destructive operations, potentially enabling denial of service, system instability, or destruction of critical system files. EPSS and KEV data are not provided, but the lack of confirmed active exploitation (no KEV mention) suggests this is not yet widely weaponized. The technical simplicity (AC:L, PR:N) and availability of a vendor security advisory (GHSA-p29x-r292-46pp) indicate this is a credible threat that should be prioritized for patching, particularly on systems running untrusted Flatpak applications. The SSVC framework would likely classify this as high technical impact (arbitrary host file deletion) with medium-to-high automatable potential given the straightforward path traversal nature.

An attacker distributes a malicious Flatpak application through third-party repositories or social engineering. When a user installs and runs this application, the malicious code triggers ld.so cache operations with carefully crafted path traversal sequences (e.g., '../../../../etc/critical-config' or '../../../../usr/bin/important-binary') during cache cleanup. Because Flatpak fails to validate these paths remain within the cache directory, the application successfully deletes arbitrary host system files, potentially rendering the system unstable or destroying critical configurations, logs, or system binaries. This represents a complete sandbox escape for destructive operations without requiring any authentication or user interaction beyond initial application launch.