CVE-2026-97027
Description
Flatpak passes through arbitrary vendor-extension keys unmodified when exporting an application's Desktop Entry (.desktop) and D-Bus Service (.service) files, instead of validating against an allowlist. A malicious Flatpak app can use this to cause denial of service (e.g. forced application restart loops) or to influence host D-Bus/systemd activation behavior beyond what the sandbox is intended to permit.
Statement
Red Hat estimates the CVSSv3.1 vector of CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L.
Exploitation requires a victim to install and run a malicious Flatpak application (UI:R), after which the unsanitized exported Desktop Entry / D-Bus Service keys take effect automatically with no additional attacker privileges or access complexity (AV:L, AC:L, PR:N). Because the exported files can influence D-Bus/systemd activation behavior on the host session outside the flatpak sandbox, this is treated as a scope change (S:C). No confidentiality or integrity impact is implied by the primary reported effect (C:N, I:N); the impact is limited to availability, via forced application restart loops or disrupted service activation (A:L).
Mitigation
Only install applications from trusted sources.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.6 | N/A | 3.6 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Changed | N/A | Changed |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
Acknowledgements
Red Hat would like to thank Markus Göllnitz for reporting this issue.
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