Flatpak · Flatpak · CVE-2021-21261
Name of the Vulnerable Software and Affected Versions:
Flatpak versions 0.11.4 through 1.8.4
Flatpak versions 1.9.0 through 1.9.3
Description:
A bug was discovered in the `flatpak-portal` service that can allow sandboxed applications to execute arbitrary code on the host system. The Flatpak portal D-Bus service (`flatpak-portal`, also known by its D-Bus service name `org.freedesktop.portal.Flatpak`) allows apps in a Flatpak sandbox to launch their own subprocesses in a new sandbox instance. In vulnerable versions, the Flatpak portal service passes caller-specified environment variables to non-sandboxed processes on the host system, and in particular to the `flatpak run` command that is used to launch the new sandbox instance. A malicious or compromised Flatpak app could set environment variables that are trusted by the `flatpak run` command, and use them to execute arbitrary code that is not in a sandbox.
Recommendations:
For versions 0.11.4 through 1.8.4, update to version 1.8.5 or later.
For versions 1.9.0 through 1.9.3, update to version 1.9.4 or later.
As a temporary workaround, consider preventing the `flatpak-portal` service from starting, but this mitigation will prevent many Flatpak apps from working correctly.