RHCOS 4 : OpenShift Container Platform 4.21.33 (RHSA-2026:66350)

high Nessus Plugin ID 345858

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Synopsis

The remote Red Hat CoreOS host is missing one or more security updates for OpenShift Container Platform 4.21.33.

Description

The remote Red Hat Enterprise Linux CoreOS 4 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:66350 advisory.

- net/http/internal/http2: golang: golang.org/x/net: Go HTTP/2: Denial of Service via malformed SETTINGS_MAX_FRAME_SIZE frame (CVE-2026-33814)

- encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal (CVE-2026-33818)

- golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing (CVE-2026-39821)

- golang: Go os.Root: Symlink following vulnerability allows directory traversal (CVE-2026-39822)

- mime: golang: Golang MIME: Denial of Service via maliciously-crafted MIME header (CVE-2026-42504)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHCOS OpenShift Container Platform 4.21.33 packages based on the guidance in RHSA-2026:66350.

Plugin Details

Severity: High

ID: 345858

File Name: rhcos-RHSA-2026-66350.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 9/15/2026

Updated: 9/15/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.19

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-33814

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:10:coreos, cpe:/o:redhat:enterprise_linux:8:coreos, cpe:/o:redhat:enterprise_linux:9:coreos, p-cpe:/a:redhat:enterprise_linux:openshift-clients-redistributable, p-cpe:/a:redhat:enterprise_linux:openshift-clients, p-cpe:/a:redhat:enterprise_linux:openshift-hyperkube, p-cpe:/a:redhat:enterprise_linux:openshift-kube-apiserver, p-cpe:/a:redhat:enterprise_linux:openshift-kube-controller-manager, p-cpe:/a:redhat:enterprise_linux:openshift-kube-scheduler, p-cpe:/a:redhat:enterprise_linux:openshift-kubelet, p-cpe:/a:redhat:enterprise_linux:openshift, p-cpe:/a:redhat:enterprise_linux:ose-crio-credential-provider

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 9/15/2026

Vulnerability Publication Date: 5/7/2026

Reference Information

CVE: CVE-2026-33814, CVE-2026-33818, CVE-2026-39821, CVE-2026-39822, CVE-2026-42504, CVE-2026-56859, CVE-2026-56860, CVE-2026-56862

CWE: 1050, 1289, 59, 606, 770, 776

RHSA: 2026:66350

Detections

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