CVE-2026-96279
Received Received - Intake

OCI Registry Hardlink Arbitrary File Disclosure in Flatpak

Publication date: 2026-09-27

Last updated on: 2026-09-27

Assigner: redhat-SADP

Description
A malicious OCI registry can hardlink arbitrary host files into the extraction directory when a user installs or updates a Flatpak application from an OCI remote, allowing disclosure of arbitrary host file contents. For system-wide installs running as root, this includes sensitive files such as /etc/shadow.

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Meta Information

Published
2026-09-27
Last Modified
2026-09-27
Generated
2026-09-28
AI Q&A
2026-09-27
EPSS Evaluated
N/A
NVD
CVE-2026-96279
EUVD
EUVD-2026-88013

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
flatpak flatpak From 1.17.0 (inc) to 1.18.0 (inc)
flatpak flatpak 1.18.1
flatpak flatpak to 1.17.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-59 The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Attack-Flow Graph

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Executive Summary

CVE-2026-96279 is a path traversal vulnerability in Flatpak affecting OCI archive extraction. When installing or updating a Flatpak app from a malicious OCI registry, the system fails to properly rebase hardlink targets during extraction. This allows an attacker to create hardlinks to arbitrary host files like /etc/shadow in the extraction directory. The vulnerability exists because hardlink targets are not rebased to the destination directory, bypassing security checks. It was introduced in Flatpak 1.17.0 and fixed in 1.18.1.

Detection Guidance

To detect this vulnerability, check your Flatpak version with 'flatpak --version'. If it is 1.17.0 or later, the system may be vulnerable. Review installed Flatpak remotes with 'flatpak remotes' to ensure none use untrusted OCI registries. Monitor for unexpected file reads or hardlinks in extraction directories during Flatpak operations.

Impact Analysis

This vulnerability allows an attacker who controls an OCI registry to read sensitive files on your system during Flatpak install or update operations. For system-wide installs running as root, attackers could access files like /etc/shadow. The impact is limited to information disclosure and requires user interaction to trigger. It does not modify files or disrupt services.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating compliance requirements for data protection standards like GDPR and HIPAA. GDPR requires protection of personal data, while HIPAA mandates safeguards for protected health information. A breach exposing such data could result in regulatory penalties and loss of compliance certifications.

Mitigation Strategies

Upgrade Flatpak to version 1.18.1 or later immediately. Avoid installing or updating Flatpak applications from untrusted OCI registries. Use only trusted sources and verify remote configurations with 'flatpak remote-modify --no-gpg-verify' if necessary. For system-wide installations, consider temporarily disabling Flatpak until patched.

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