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High USN-4721-1 1 CVE

flatpak vulnerability

Published Feb 4, 2021 · Updated Apr 22, 2026

Ecosystem: Ubuntu

Summary

Simon McVittie discovered that flatpak-portal service allowed sandboxed
applications to execute arbitrary code on the host system (a sandbox
escape). A malicious user could create a Flatpak application that set
environment variables, trusted by the Flatpak "run" command, and use it
to execute arbitrary code outside the sandbox.

Fixed packages 2

ReleasePackageFixed in
Ubuntu · 18.04 LTS 18.04:LTS flatpak 1.0.9-0ubuntu0.2
Ubuntu · 20.04 LTS 20.04:LTS flatpak 1.6.5-0ubuntu0.2

Vulnerabilities 1

  • High 7.3
    CVE-2021-21261

    Flatpak sandbox escape via spawn portal

    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). Th…

    Flatpak Flatpak flatpak flatpak Debian Ubuntu Alpine

References

  • report
    https://ubuntu.com/security/CVE-2021-21261