Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In versions prior to 1.10.4 and 1.12.0, Flatpak apps with direct access to AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can trick portals and other host-OS services into treating the Flatpak app as though it was an ordinary, non-sandboxed host-OS process. They can do this by manipulating the VFS using recent mount-related syscalls that are not blocked by Flatpak's denylist seccomp filter, in order to substitute a crafted `/.flatpak-info` or make that file disappear entirely. Flatpak apps that act as clients for AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can escalate the privileges that the corresponding services will believe the Flatpak app has. Note that protocols that operate entirely over the D-Bus session bus (user bus), system bus or accessibility bus are not affected by this. This is due to the use of a proxy process `xdg-dbus-proxy`, whose VFS cannot be manipulated by the Flatpak app, when interacting with these buses. Patches exist for versions 1.10.4 and 1.12.0, and as of time of publication, a patch for version 1.8.2 is being planned. There are no workarounds aside from upgrading to a patched version.
History

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2021-10-08T00:00:00

Updated: 2024-08-04T02:59:31.388Z

Reserved: 2021-09-15T00:00:00

Link: CVE-2021-41133

cve-icon Vulnrichment

Updated: 2024-08-04T02:59:31.388Z

cve-icon NVD

Status : Modified

Published: 2021-10-08T14:15:08.723

Modified: 2024-11-21T06:25:33.023

Link: CVE-2021-41133

cve-icon Redhat

Severity : Important

Publid Date: 2021-10-08T00:00:00Z

Links: CVE-2021-41133 - Bugzilla