CVE-2026-19706
Description
During ABI bootstrap, the bootstrap node's approve-csr.service approves and signs every CSR without identity validation.
An attacker on the install network can retrieve the unauthenticated Ignition file (ports 22623/22624), extract a limited kubeconfig, submit a CSR for CN=system:admin, receive the signed certificate, and gain full cluster-admin access.
Exploitable only during the narrow bootstrap window.
Statement
During an OpenShift Agent-Based Installation (ABI), an attacker with network access to the bootstrap node's Kubernetes API can gain cluster-admin privileges.
This flaw arises from the approve-csr.service unconditionally approving CertificateSigningRequests, allowing an attacker to submit a crafted request for system:admin identity. Exploitation is limited to the brief ABI bootstrap window and requires network adjacency to the API server.
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 | 8.3 | N/A | N/A |
| Attack Vector | Adjacent Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Changed | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context
Exposing critical functionality essentially provides an attacker with the privilege level of that functionality. The consequences will depend on the associated functionality, but they can range from reading or modifying sensitive data, accessing administrative or other privileged functionality, or possibly even executing arbitrary code.
Acknowledgements
Red Hat would like to thank Chi Zhang (cz21) (External Researcher (August 8, 2026)) and Christopher Lusk (North Echo Security Research (August 26, 2026)) for reporting this issue.
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