Arbitrary Code Injection Affecting flatpak-builder package, versions <0:1.0.0-10.amzn2


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.05% (25th percentile)

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  • Snyk IDSNYK-AMZN2-FLATPAKBUILDER-1693256
  • published27 Sept 2021
  • disclosed14 Jan 2021

Introduced: 14 Jan 2021

CVE-2021-21261  (opens in a new tab)
CWE-74  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2 flatpak-builder to version 0:1.0.0-10.amzn2 or higher.
This issue was patched in ALAS2-2021-1597.

NVD Description

Note: Versions mentioned in the description apply only to the upstream flatpak-builder package and not the flatpak-builder package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. A bug was discovered in the flatpak-portal service that can allow sandboxed applications to execute arbitrary code on the host system (a sandbox escape). This sandbox-escape bug is present in versions from 0.11.4 and before fixed versions 1.8.5 and 1.10.0. 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, either with the same security settings as the caller or with more restrictive security settings. For example, this is used in Flatpak-packaged web browsers such as Chromium to launch subprocesses that will process untrusted web content, and give those subprocesses a more restrictive sandbox than the browser itself. 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. As a workaround, this vulnerability can be mitigated by preventing the flatpak-portal service from starting, but that mitigation will prevent many Flatpak apps from working correctly. This is fixed in versions 1.8.5 and 1.10.0.

CVSS Scores

version 3.1