CVE-2026-90616

A flaw was found in Flatpak. A malicious sandboxed application can exploit missing symlink protection during the creation and bind-mounting of app data directories. By manipulating attacker-controlled path components, a malicious symlink can redirect these directories to arbitrary locations on the host system. This allows the sandboxed application to gain arbitrary read and write access to host files, which can be escalated to arbitrary code execution on the host.

This vulnerability is rated with an Important impact rather than Critical because successful exploitation requires a user to run an untrusted or compromised sandboxed application locally, yet it warrants higher severity than Moderate due to complete sandbox escape resulting in host-level code execution. In Red Hat Enterprise Linux environments, Flatpak is primarily utilized on workstation installations or desktop sessions to isolate third-party software, while standard server deployments typically do not execute containerized desktop applications. Because the flaw bypasses container isolation boundaries by traversing symbolic links during runtime directory mounting, an attacker inside a restricted sandbox can compromise the integrity and confidentiality of the host operating system.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To reduce the risk of exploitation, users should only install Flatpak applications from trusted sources. Regularly reviewing and removing unnecessary or untrusted Flatpak applications can further limit exposure.