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Arbitrary Code Injection The advisory has been revoked - it doesn't affect any version of package flatpak  (opens in a new tab)

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EPSS
1.55% (72nd percentile)

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  • Snyk IDSNYK-DEBIAN9-FLATPAK-1085177
  • published12 Mar 2021
  • disclosed11 Mar 2021
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Introduced: 11 Mar 2021

CVE-2021-21381  (opens in a new tab)
CWE-74  (opens in a new tab)

Amendment

The Debian security team deemed this advisory irrelevant for Debian:9.

NVD Description

Note: Versions mentioned in the description apply only to the upstream flatpak package and not the flatpak package as distributed by Debian.

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In Flatpack since version 0.9.4 and before version 1.10.2 has a vulnerability in the "file forwarding" feature which can be used by an attacker to gain access to files that would not ordinarily be allowed by the app's permissions. By putting the special tokens @@ and/or @@u in the Exec field of a Flatpak app's .desktop file, a malicious app publisher can trick flatpak into behaving as though the user had chosen to open a target file with their Flatpak app, which automatically makes that file available to the Flatpak app. This is fixed in version 1.10.2. A minimal solution is the first commit "Disallow @@ and @@U usage in desktop files". The follow-up commits "dir: Reserve the whole @@ prefix" and "dir: Refuse to export .desktop files with suspicious uses of @@ tokens" are recommended, but not strictly required. As a workaround, avoid installing Flatpak apps from untrusted sources, or check the contents of the exported .desktop files in exports/share/applications/*.desktop (typically ~/.local/share/flatpak/exports/share/applications/*.desktop and /var/lib/flatpak/exports/share/applications/*.desktop) to make sure that literal filenames do not follow @@ or @@u.

References