CVE-2026-107466
Description
A flaw was found in flatpak-builder. This vulnerability allows an attacker to cause information disclosure by convincing a user or continuous integration (CI) system to process a crafted build manifest. By specifying local file Uniform Resource Identifiers (URIs) within source download definitions, the builder bypasses directory confinement checks. As a result, sensitive host files accessible to the build process can be read and incorporated into the build artifacts.
Statement
This vulnerability is rated as Moderate severity because exploitation requires an attacker to convince a user or automated pipeline to execute a malicious manifest, rather than permitting unauthenticated remote execution. In Red Hat Enterprise Linux, flatpak-builder is an on-demand developer utility rather than an exposed network daemon or persistent service. Although the directory confinement mechanism does not isolate local URI references during source downloads, read operations remain constrained to host files accessible by the user account executing the command.
Mitigation
If Flatpak packaging is not required on the system, remove the flatpak-builder package to eliminate exposure:
# dnf remove flatpak-builder
For development environments and continuous integration pipelines where flatpak-builder is necessary, apply the following operational controls:
1. Avoid processing build manifests from untrusted or unverified third-party sources.
2. Execute builds within isolated, ephemeral container or virtual machine environments where sensitive host files and credentials are not mounted or accessible.
3. Implement pre-build pipeline checks to reject manifests containing `file://` URI schemes in `type: file` or `type: archive` source definitions.
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 | 6.1 | N/A | 6.1 |
| 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 | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity
Technical Impact: Modify Files or Directories
The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality
Technical Impact: Read Files or Directories
The attacker may be able to read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of protection mechanisms such as authentication, it has the potential to lock out product users.
Acknowledgements
This issue was discovered by Found by AISLE in partnership with Red Hat.
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