The vulnerability allows an application running within a Flatpak sandbox to escape the confinement by creating symlinks that resolve to arbitrary host paths when passed to the sandbox-expose options. Once the host paths are mounted, the app gains unrestricted read and write access to all files on the host system and may execute code in the host context. This represents a significant compromise of confidentiality, integrity, and availability of the host environment. The weakness aligns with path traversal (CWE‑59) and file inclusion (CWE‑61).

All installations of Flatpak using the Flatpak portal preceding version 1.16.4 are affected. Users of the flatpak:flatpak product that rely on sandbox-expose feature must verify their current version and update. No other vendors or products are listed as impacted.

The CVSS score of 9.3 classifies the flaw as critical, and while an EPSS score is not publicly available, the design of SandBox can be abused by any app that can be run locally by the user, implying a high likelihood of exploitation. The flaw is not listed in KEV, suggesting it may not yet be commonly exploited in the wild. The attack vector is inferred to be local, requiring an attacker to run a malicious or compromised Flatpak application that utilizes sandbox-expose. If such an app is executed, it can reach host files and potentially run code on the host.