CVE - CVE-2021-21381

CVE-ID
CVE-2021-21381	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
CONFIRM:https://github.com/flatpak/flatpak/security/advisories/GHSA-xgh4-387p-hqpp URL:https://github.com/flatpak/flatpak/security/advisories/GHSA-xgh4-387p-hqpp DEBIAN:DSA-4868 URL:https://www.debian.org/security/2021/dsa-4868 FEDORA:FEDORA-2021-26ad138ffa URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WXNVFOIB6ZP4DGOVKAM25T6OIEP3YLGV/ FEDORA:FEDORA-2021-fe7decc595 URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2MXXLXC2DPJ45HSMTI5MZYHMYEGQN6AA/ MISC:https://github.com/flatpak/flatpak/commit/8279c5818425b6812523e3805bbe242fb6a5d961 URL:https://github.com/flatpak/flatpak/commit/8279c5818425b6812523e3805bbe242fb6a5d961 MISC:https://github.com/flatpak/flatpak/commit/a7401e638bf0c03102039e216ab1081922f140ae URL:https://github.com/flatpak/flatpak/commit/a7401e638bf0c03102039e216ab1081922f140ae MISC:https://github.com/flatpak/flatpak/commit/eb7946bb6248923d8c90fe9b84425fef97ae580d URL:https://github.com/flatpak/flatpak/commit/eb7946bb6248923d8c90fe9b84425fef97ae580d MISC:https://github.com/flatpak/flatpak/pull/4156 URL:https://github.com/flatpak/flatpak/pull/4156 MISC:https://github.com/flatpak/flatpak/releases/tag/1.10.2 URL:https://github.com/flatpak/flatpak/releases/tag/1.10.2
Assigning CNA
GitHub (maintainer security advisories)
Date Record Created
20201222	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20201222)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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