CVE-2021-43860

Unauthorized sandbox permissions via null-byte metadata truncation

Published Jan 12, 2022 · Updated Aug 4, 2024

Privilege management flaw in Flatpak before 1.10.6 and 1.11.0 through 1.12.2 allows attackers to obtain hidden sandbox permissions. Permission validation reads an app's metadata file as a null-terminated C string, so it compares only bytes before an embedded null against xa.metadata while later bytes are applied. A user must install or update a maliciously crafted app from an untrusted source, after which the app receives permissions that were not displayed for consent.

CVSS severity8.2
High
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege management flaw in Flatpak before 1.10.6 and 1.11.0 through 1.12.2 allows attackers to obtain hidden sandbox permissions. Permission validation reads an app's metadata file as a null-terminated C string, so it compares only bytes before an embedded null against xa.metadata while later bytes are applied. A user must install or update a maliciously crafted app from an untrusted source, after which the app receives permissions that were not displayed for consent.

The record

CVE
CVE-2021-43860
Published
Jan 12, 2022
Updated
Aug 4, 2024
Vendor
Flatpak
Product
Flatpak
Classifications
CWE-269, CWE-276
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.10.6
  2. Affected versionversion=>= 1.11.0, < 1.12.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Flatpak · Flatpakversion=< 1.10.6; version=>= 1.11.0, < 1.12.3

Published CVSS scores

8.6NISTCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
6.8NISTAV:N/AC:M/Au:N/C:P/I:P/A:P
8.2GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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