CVE-2026-39821Network attack vectorHinoki check available

Privilege escalation via ASCII-only Punycode acceptance

Published May 22, 2026 · Updated Aug 28, 2026

Improper hostname validation in Go net/http before 1.25.13 and x/net/idna before 0.55.0 allows attackers to bypass access controls. Profile.process and net/http IDNA authority handling accept an xn-- label when Punycode decoding yields only ASCII, returning the decoded hostname instead of an error. Exploitation requires an application to authorize the encoded hostname before converting it to Unicode; the resulting equivalence can grant access to a hostname that the policy denied.

CVSS severity8.2

High

EPSS probability0.69%

Next 30 days · Sep 16, 2026

Known exploitationUnconfirmed

Based on sourced intelligence

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Summary

What happened

The record

CVE: CVE-2026-39821
Published: May 22, 2026
Updated: Aug 28, 2026

Vendor: 389 Directory Server
Product: Assisted Installer for OpenShift Container Platform
Classifications: CWE-1289

Attack vector: network
Privileges: authenticated

Timeline

How it unfolded

May 22, 2026CVE publishedPublication date reported by the CVE source.
Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork

Required privilegesauthenticated

What is affected?

389 Directory Server · Assisted Installer for OpenShift Container PlatformAffected versions are unavailable in this record.

389 Directory Server · Red Hat QuayAffected versions are unavailable in this record.

389 Directory Server · Machine Deletion Remediation OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift ServerlessAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Distributed TracingAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Service MeshAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift LightspeedAffected versions are unavailable in this record.

389 Directory Server · cert-manager Operator for Red Hat OpenShiftAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift AIAffected versions are unavailable in this record.

389 Directory Server · OpenShift API for Data ProtectionAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Compliance OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat Edge ManagerAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Dev SpacesAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift for Windows ContainersAffected versions are unavailable in this record.

golang.org/x/net · golang.org/x/net/idnaversion=0 <0.55.0

389 Directory Server · OpenShift Developer Tools and ServicesAffected versions are unavailable in this record.

389 Directory Server · Red Hat Ceph StorageAffected versions are unavailable in this record.

389 Directory Server · Migration Toolkit for ApplicationsAffected versions are unavailable in this record.

389 Directory Server · Security Profiles OperatorAffected versions are unavailable in this record.

Go standard library · net/httpversion=0 <1.25.13; version=1.26.0-0 <1.26.6; version=1.27.0-0 <1.27.0-rc.3

389 Directory Server · Red Hat Enterprise Linux AIAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Data FoundationAffected versions are unavailable in this record.

389 Directory Server · multicluster engine for Kubernetes 2.6Affected versions are unavailable in this record.

389 Directory Server · Red Hat Advanced Cluster Security for Kubernetes 4.11Affected versions are unavailable in this record.

389 Directory Server · Zero Trust Workload Identity Manager - Tech PreviewAffected versions are unavailable in this record.

389 Directory Server · Node Healthcheck OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat Advanced Cluster Management for KubernetesAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift BuildsAffected versions are unavailable in this record.

389 Directory Server · Red Hat Advanced Cluster Security for KubernetesAffected versions are unavailable in this record.

389 Directory Server · Multicluster Global HubAffected versions are unavailable in this record.

389 Directory Server · ExternalDNS OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat Migration Toolkit for ContainersAffected versions are unavailable in this record.

389 Directory Server · Fence Agents Remediation OperatorAffected versions are unavailable in this record.

389 Directory Server · External Secrets Operator for Red Hat OpenShiftAffected versions are unavailable in this record.

389 Directory Server · Network Observability OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 9.4 Update Services for SAP SolutionsAffected versions are unavailable in this record.

389 Directory Server · Red Hat Ansible Automation PlatformAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.

389 Directory Server · DevWorkspace OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift VirtualizationAffected versions are unavailable in this record.

389 Directory Server · File Integrity OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat Streams for Apache KafkaAffected versions are unavailable in this record.

Go standard library · net/http/internal/http2version=0 <1.25.13; version=1.26.0-0 <1.26.6; version=1.27.0-0 <1.27.0-rc.3

389 Directory Server · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.

389 Directory Server · Red Hat Hardened ImagesAffected versions are unavailable in this record.

389 Directory Server · Red Hat Ceph Storage 9Affected versions are unavailable in this record.

389 Directory Server · Multiarch Tuning OperatorAffected versions are unavailable in this record.

389 Directory Server · Workload Availability for Red Hat OpenShiftAffected versions are unavailable in this record.

389 Directory Server · Red Hat Connectivity LinkAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Container Platform 4.22Affected versions are unavailable in this record.

389 Directory Server · Red Hat OpenStack PlatformAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift GitOpsAffected versions are unavailable in this record.

389 Directory Server · Confidential Compute Attestation OperatorAffected versions are unavailable in this record.

389 Directory Server · multicluster engine for Kubernetes 2.8Affected versions are unavailable in this record.

389 Directory Server · Gatekeeper 3Affected versions are unavailable in this record.

389 Directory Server · Power monitoring for Red Hat OpenShiftAffected versions are unavailable in this record.

389 Directory Server · Red Hat Certification Program for Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

389 Directory Server · Deployment Validation OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat 3scale API ManagementAffected versions are unavailable in this record.

389 Directory Server · Zero Trust Workload Identity ManagerAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Cluster Observability OperatorAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift LoggingAffected versions are unavailable in this record.

389 Directory Server · Red Hat Web TerminalAffected versions are unavailable in this record.

389 Directory Server · Red Hat SatelliteAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Container PlatformAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Cluster Manager CLIAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

389 Directory Server · multicluster engine for Kubernetes 2.9Affected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift PipelinesAffected versions are unavailable in this record.

389 Directory Server · Red Hat Lightspeed for RuntimesAffected versions are unavailable in this record.

389 Directory Server · multicluster engine for KubernetesAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Container Platform 4Affected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 7 Extended Lifecycle SupportAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 10.0 Extended Update SupportAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 9.6 Extended Update SupportAffected versions are unavailable in this record.

389 Directory Server · Red Hat Trusted Artifact SignerAffected versions are unavailable in this record.

389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Service on AWSAffected versions are unavailable in this record.

389 Directory Server · Red Hat OpenShift Container Platform 4.20Affected versions are unavailable in this record.

Published CVSS scores

8.2Red HatCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

9.6CISA ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026

Latest reporting daySep 16, 2026

Latest daily unique IPsUnavailable

Prior 30-day averageUnavailable

SourceShadowserver honeypots (KEV)

Vectornetwork

Privilegesauthenticated

Known exploitationUnconfirmed

Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1289Improper Validation of Unsafe Equivalence in Input

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

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