CVE-2026-97029
Received Received - Intake

Flatpak Sandbox Escape via kill(0) Process Termination

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: redhat-SADP

Description
Flatpak's process ID namespace separation does not prevent a sandboxed app's kill(0, signal) or killpg(0, signal) calls from reaching processes outside the sandbox that share the same process group. A malicious or compromised Flatpak app can use this to cause denial of service by terminating processes outside its sandbox, such as the desktop shell.

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Meta Information

Published
2026-09-29
Last Modified
2026-09-29
Generated
2026-09-29
AI Q&A
2026-09-29
EPSS Evaluated
N/A
NVD
CVE-2026-97029
EUVD
EUVD-2026-88627

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
flatpak flatpak to 1.18.4 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-653 The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.

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Executive Summary

This vulnerability in Flatpak allows a sandboxed app to send signals like kill(0, signal) or killpg(0, signal) to processes outside its sandbox that share the same process group. This bypasses intended isolation, letting a malicious app terminate critical system processes such as the desktop shell, causing a denial of service.

Detection Guidance

To detect this vulnerability, check the Flatpak version installed on your system. Run: flatpak --version. If the version is below 1.18.4, the system is vulnerable. Additionally, monitor for unexpected process terminations or desktop crashes when running Flatpak apps.

Impact Analysis

A malicious or compromised Flatpak app could terminate important system processes like GNOME Shell, crashing your desktop session or causing a denial of service. The attack requires you to run the app but then triggers automatically without extra privileges.

Compliance Impact

This vulnerability primarily impacts system availability by allowing sandboxed apps to terminate critical processes like the desktop shell. It does not directly affect data confidentiality or integrity, which are key focus areas for GDPR and HIPAA. However, repeated denial-of-service conditions could disrupt system operations, potentially interfering with compliance monitoring or audit logging.

Mitigation Strategies

Upgrade Flatpak to version 1.18.4 or later. If upgrading is not possible, run Flatpak apps in a new session using setsid flatpak run ... or a new process group with setpgid(0, 0). Avoid running untrusted Flatpak applications until patched.

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