8.2

CVE-2021-21381: debian debian_linux Injection

CVSS: 8.2v3.1HighModified
AliasesMGASA-2021-0145RHSA-2021:1002RHSA-2021:1068
Published 11-03-2021Last modified 03-08-2024
Open JSON

Vulnerability summary

CVE-2021-21381 is a high (CVSS 8.2) Injection vulnerability in debian debian_linux. EPSS estimates a 1.55% chance of exploitation in the next 30 days, higher than 74.6% of scored vulnerabilities.

Overall risk
33/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.2/10
010
High · v3.1 (NVD)
EPSS score
1.55%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 1
MGASA-2021-0143SUSE-SU-2022:2990-1

Timeline

  1. 11-03-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

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`.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

1.55%

Chance of exploitation in the next 30 days

Percentile

75%

Versus all other CVEs

30-day change

0.00 pp

From 1.55% on 20-09-2026

20-09-202620-10-2026
EPSS score
1.55%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Redhat11 products
  • flatpak< 0:1.0.9-11.el7_9 | < 0:1.6.2-6.el8_3 | < 0:1.6.2-5.el8_2 | < 0:1.0.9-4.el8_1
  • flatpak-builder< 0:1.0.0-11.el7_9
  • flatpak-debuginfo< 0:1.0.9-11.el7_9 | < 0:1.6.2-6.el8_3 | < 0:1.6.2-5.el8_2 | < 0:1.0.9-4.el8_1
  • flatpak-debugsource< 0:1.6.2-6.el8_3 | < 0:1.6.2-5.el8_2 | < 0:1.0.9-4.el8_1
  • flatpak-devel< 0:1.0.9-11.el7_9
Debian2 products
Fedoraproject1 product
Flatpak1 product
Mageia1 product
  • flatpak< 1.10.2-1.mga8
Ubuntu1 product
  • flatpak< 1.0.9-0ubuntu0.3 | < 1.6.5-0ubuntu0.3

6 vendors · 17 products

References

29 links
Show all 29 references