Summary
Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2021-41133: 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.
Fixed packages 5
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2 | flatpak | 0:1.0.9-10.amzn2.0.2 |
| Amazon Linux · 2 | flatpak-builder | 0:1.0.0-10.amzn2.0.2 |
| Amazon Linux · 2 | flatpak-debuginfo | 0:1.0.9-10.amzn2.0.2 |
| Amazon Linux · 2 | flatpak-devel | 0:1.0.9-10.amzn2.0.2 |
| Amazon Linux · 2 | flatpak-libs | 0:1.0.9-10.amzn2.0.2 |
Vulnerabilities 1
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High 8.8
Sandbox bypass via recent VFS-manipulating syscalls
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…
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2021-41133.html