CVE-2026-66808
Description
A flaw was found in hypershift-addon-operator. A hub-cluster administrator with write access to the hypershift-operator-install-flags ConfigMap can inject malicious command-line arguments into the privileged install Job. This vulnerability, known as argument injection, allows the attacker to pull arbitrary container images and gain full administrative control (cluster-admin code execution) on managed spoke clusters.
Statement
This Important flaw in Multicluster Engine for Kubernetes allows a hub-cluster namespace administrator with write access to the hypershift-operator-install-flags ConfigMap to inject arbitrary command-line arguments into a privileged install Job. This enables privilege escalation to cluster-admin on managed spoke clusters, bypassing security boundaries within the multi-cluster environment.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.7 | N/A | 8.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | High | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Red Hat CVSS v3 Score Explanation
CWE-88 Argument Injection — hub namespace-admin injects arbitrary CLI flags via ConfigMap into privileged install Job, achieving cluster-admin on spoke
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Other
Technical Impact: Execute Unauthorized Code or Commands; Alter Execution Logic; Read Application Data; Modify Application Data
An attacker could include arguments that allow unintended commands or code to be executed, allow sensitive data to be read or modified or could cause other unintended behavior.
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