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Flatpak CVE-2026-76925

| EUVDEUVD-2026-71774 MEDIUM
Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367)
2026-09-04 redhat GHSA-639f-3fwc-hmpx
5.8
CVSS 3.1 · Vendor: redhat
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Severity by source

Vendor (redhat) PRIMARY
5.8 MEDIUM
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L
vuln.today AI
5.8 MEDIUM

Local access and a low-privileged account required; AC:H reflects the race condition timing requirement; C:H for potential arbitrary file read via redirected chmod.

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L
4.0 AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
SUSE
7.0 HIGH
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Red Hat
5.8 MEDIUM
qualitative

Primary rating from Vendor (redhat).

CVSS VectorVendor: redhat

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
Low

Lifecycle Timeline

2
Analysis Generated
Sep 04, 2026 - 21:51 vuln.today
CVE Published
Sep 04, 2026 - 21:02 cve.org
MEDIUM 5.8

DescriptionCVE.org

A flaw was found in Flatpak. A Time-of-check to time-of-use (TOCTOU) race condition exists in the org.freedesktop.Flatpak.SystemHelper component. This vulnerability occurs because a privileged chmod operation executes before the OSTree repository validation within the Deploy() function. An attacker can exploit this timing window to redirect symlinks to arbitrary files, potentially leading to unauthorized file manipulation or information disclosure.

AnalysisAI

Flatpak's org.freedesktop.Flatpak.SystemHelper D-Bus service contains a TOCTOU race condition in the Deploy() function where a privileged chmod executes before OSTree repository validation completes, allowing a local low-privileged attacker to redirect symlinks to arbitrary system files within that timing window. A successful exploit can yield high-confidentiality impact (reading privileged files) and limited integrity and availability impact (CVSS C:H/I:L/A:L), as the unguarded chmod can be inherited by attacker-controlled symlink targets. …

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Attack ChainAIDerived

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Vulnerability AssessmentAI

Exploitation Exploitation requires a local authenticated account with at least standard user (low) privileges on an affected RHEL system running Flatpak - the attacker must be able to invoke the `Deploy()` method on the `org.freedesktop.Flatpak.SystemHelper` D-Bus service, which is typically permitted to console or session users by default polkit policy. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The provided CVSS 3.1 vector (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L) scores 5.8 (Medium), which accurately reflects the real-world constraint: exploitation requires a local, low-privileged account and the ability to win a timing-sensitive race condition, making reliable exploitation non-trivial. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation Apply vendor-supplied errata from Red Hat for the affected RHEL releases via the advisory at https://access.redhat.com/security/cve/CVE-2026-76925; a specific patched Flatpak package version is not confirmed in the available data, so monitor Red Hat Bugzilla entry 2520099 for errata publication. … Detailed patch versions, workarounds, and compensating controls in full report.

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Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Module for Desktop Applications 15 SP7 Affected
SUSE Linux Enterprise Server 15 SP7 Affected
SUSE Linux Enterprise Server 16.0 Affected
SUSE Linux Enterprise Server 16.1 Affected

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CVE-2026-76925 vulnerability details – vuln.today

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