#VU51443 Improper Neutralization of Special Elements in Output Used by a Downstream Component in Flatpak - CVE-2021-21381
Published: March 14, 2021
Vulnerability identifier: #VU51443
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2021-21381
CWE-ID: CWE-74
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Flatpak
Flatpak
Software vendor:
Flatpak
Flatpak
Description
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to improper input validation within the "file forwarding" feature. 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.
Remediation
Install updates from vendor's website.
External links
- https://github.com/flatpak/flatpak/commit/8279c5818425b6812523e3805bbe242fb6a5d961
- https://github.com/flatpak/flatpak/commit/a7401e638bf0c03102039e216ab1081922f140ae
- https://github.com/flatpak/flatpak/commit/eb7946bb6248923d8c90fe9b84425fef97ae580d
- https://github.com/flatpak/flatpak/pull/4156
- https://github.com/flatpak/flatpak/releases/tag/1.10.2
- https://github.com/flatpak/flatpak/security/advisories/GHSA-xgh4-387p-hqpp
- https://www.debian.org/security/2021/dsa-4868