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Fencer Vulns
high 8.2

CVE-2021-43860 json

Permissions granted to applications can be hidden from the user at install time

published 2022-01-12 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-30724

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits
0
none known

Summary

Flatpak is a Linux application sandboxing and distribution framework. Prior to versions 1.12.3 and 1.10.6, Flatpak doesn't properly validate that the permissions displayed to the user for an app at install time match the actual permissions granted to the app at runtime, in the case that there's a null byte in the metadata file of an app. Therefore apps can grant themselves permissions without the consent of the user. Flatpak shows permissions to the user during install by reading them from the "xa.metadata" key in the commit metadata. This cannot contain a null terminator, because it is an untrusted GVariant. Flatpak compares these permissions to the *actual* metadata, from the "metadata" file to ensure it wasn't lied to. However, the actual metadata contents are loaded in several places where they are read as simple C-style strings. That means that, if the metadata file includes a null terminator, only the content of the file from *before* the terminator gets compared to xa.metadata. Thus, any permissions that appear in the metadata file after a null terminator are applied at runtime but not shown to the user. So maliciously crafted apps can give themselves hidden permissions. Users who have Flatpaks installed from untrusted sources are at risk in case the Flatpak has a maliciously crafted metadata file, either initially or in an update. This issue is patched in versions 1.12.3 and 1.10.6. As a workaround, users can manually check the permissions of installed apps by checking the metadata file or the xa.metadata key on the commit metadata.

Patch / fix

  • flatpak flatpak 1.10.6
  • flatpak Debian 14, Debian 13, Debian 12 1.12.3-1

debian advisories DEBIAN-CVE-2021-43860

  • flatpak RHEL 8 1.8.7-1.el8
  • flatpak-libs RHEL 8 1.8.7-1.el8
  • flatpak-selinux RHEL 8 1.8.7-1.el8
  • flatpak-session-helper RHEL 8 1.8.7-1.el8

red hat advisories RHSA-2022:1792

  • flatpak SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +3 more 1.2.3-150100.4.8.1
  • flatpak SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLES 15 SP2-BCL +8 more 1.10.7-4.12.1

suse advisories SUSE-SU-2022:3284-1SUSE-SU-2022:0712-1

  • flatpak openSUSE Tumbleweed 1.12.3-1.1
  • flatpak openSUSE Leap 15.3 1.10.7-4.12.1

opensuse advisories openSUSE-SU-2024:11740-1openSUSE-SU-2022:0712-1

  • flatpak AlmaLinux 8 1.8.7-1.el8
  • flatpak-libs AlmaLinux 8 1.8.7-1.el8
  • flatpak-selinux AlmaLinux 8 1.8.7-1.el8
  • flatpak-session-helper AlmaLinux 8 1.8.7-1.el8

almalinux advisories ALSA-2022:1792

  • flatpak Rocky Linux 8 1.8.7-1.el8

rocky linux advisories RLSA-2022:1792

  • flatpak Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 1.12.3-r0

alpine advisories ALPINE-CVE-2021-43860

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-43860 updated cvss 8.2

flatpak: Permissions granted to applications can be hidden from the user at install time

  • Red Hat Enterprise Linux AppStream (v. 8) flatpak 1.8.7-1.el8, flatpak-libs 1.8.7-1.el8, flatpak-selinux 1.8.7-1.el8, flatpak-session-helper 1.8.7-1.el8 Red Hat Enterprise Linux CRB (v. 8) flatpak 1.8.7-1.el8, flatpak-session-helper 1.8.7-1.el8
    fixed: vendor fix RHSA-2022:1792
  • Red Hat Enterprise Linux 7 flatpak, flatpak-libs, flatpak-builder Red Hat Enterprise Linux 9 flatpak, flatpak-libs, flatpak-selinux, flatpak-session-helper
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.44% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
NVD 3.1 8.6 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • flatpak flatpak

Classification

Weakness
  • CWE-269 Improper Privilege Management
  • CWE-276 Incorrect Default Permissions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.