Alibaba Cloud Linux 3 : 0001: flatpak (ALINUX3-SA-2021:0001)

high Nessus Plugin ID 236494

Synopsis

The remote Alibaba Cloud Linux host is missing one or more security updates.

Description

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by a vulnerability as referenced in the ALINUX3-SA-2021:0001 advisory.

Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

CVE-2021-21261:
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.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

Plugin Details

Severity: High

ID: 236494

File Name: alinux3_sa_2021-0001.nasl

Version: 1.1

Type: local

Family: Alibaba Cloud Linux Local Security Checks

Published: 5/14/2025

Updated: 5/14/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.5

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2021-21261

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:alibabacloud:alibaba_cloud_linux_3, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-tests, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-debugsource, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-selinux, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-tests-debuginfo, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-debuginfo, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-libs-debuginfo, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-session-helper, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-session-helper-debuginfo, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-devel, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-libs

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/Alibaba/release, Host/Alibaba/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 2/7/2021

Vulnerability Publication Date: 1/14/2021

Reference Information

CVE: CVE-2021-21261

Detections

Analytics