Ubuntu update for flatpak
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2021-21381 |
| CWE-ID | CWE-74 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
Ubuntu Operating systems & Components / Operating system flatpak (Ubuntu package) Operating systems & Components / Operating system package or component libflatpak0 (Ubuntu package) Operating systems & Components / Operating system package or component |
| Vendor | Canonical Ltd. |
Security Bulletin
This security bulletin contains one medium risk vulnerability.
1) Improper Neutralization of Special Elements in Output Used by a Downstream Component
EUVDB-ID: #VU51443
Risk: Medium
CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-21381
Exploit availability: No
DescriptionThe 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.
MitigationUpdate the affected package flatpak to the latest version.
Vulnerable software versionsUbuntu: 18.04 - 20.10
flatpak (Ubuntu package): before 1.8.2-1ubuntu0.2
libflatpak0 (Ubuntu package): before 1.8.2-1ubuntu0.2
External linkshttp://ubuntu.com/security/notices/USN-4951-1
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
