Vulnerability details

CVE-2026-39821

Go standard library net/httpGo standard library net/http/internal/http2Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2Red Hat Compliance OperatorRed Hat Confidential Compute AttestationRed Hat Deployment Validation Operator

Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna

CVSS 3.1
8.2High

Official description

The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject "example.com" but permit "xn--example-.com". If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name "example.com".

CVSS scores

ScoreVersionSourceVector
9.6Critical 3.1 CISA ADP / Vulnrichment (CISA-ADP) CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
8.2High 3.1 CVEProject cvelistV5 (CNA) (redhat-SADP) CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

Affected products

VendorProductVersionsSource
Go standard library net/http v < 1.25.13 CVEProject cvelistV5 (CNA)
Go standard library net/http 1.26.0-0 ≤ v < 1.26.6 CVEProject cvelistV5 (CNA)
Go standard library net/http 1.27.0-0 ≤ v < 1.27.0-rc.3 CVEProject cvelistV5 (CNA)
Go standard library net/http/internal/http2 v < 1.25.13 CVEProject cvelistV5 (CNA)
Go standard library net/http/internal/http2 1.26.0-0 ≤ v < 1.26.6 CVEProject cvelistV5 (CNA)
Go standard library net/http/internal/http2 1.27.0-0 ≤ v < 1.27.0-rc.3 CVEProject cvelistV5 (CNA)
Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 All CVEProject cvelistV5 (CNA)
Red Hat Compliance Operator All CVEProject cvelistV5 (CNA)
Red Hat Confidential Compute Attestation All CVEProject cvelistV5 (CNA)
Red Hat Confidential Compute Attestation All CVEProject cvelistV5 (CNA)
Red Hat Deployment Validation Operator All CVEProject cvelistV5 (CNA)
Red Hat External Secrets Operator for Red Hat OpenShift All CVEProject cvelistV5 (CNA)
Red Hat ExternalDNS Operator All CVEProject cvelistV5 (CNA)
Red Hat ExternalDNS Operator All CVEProject cvelistV5 (CNA)
Red Hat Fence Agents Remediation Operator All CVEProject cvelistV5 (CNA)
Red Hat File Integrity Operator All CVEProject cvelistV5 (CNA)
Red Hat Gatekeeper 3 All CVEProject cvelistV5 (CNA)
Red Hat Machine Deletion Remediation Operator All CVEProject cvelistV5 (CNA)
Red Hat Multiarch Tuning Operator All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Multicluster Engine for Kubernetes All CVEProject cvelistV5 (CNA)
Red Hat Network Observability Operator All CVEProject cvelistV5 (CNA)
Red Hat Node HealthCheck Operator All CVEProject cvelistV5 (CNA)
Red Hat Node HealthCheck Operator All CVEProject cvelistV5 (CNA)
Red Hat Node HealthCheck Operator All CVEProject cvelistV5 (CNA)
Red Hat OpenShift API for Data Protection All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Developer Tools and Services All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Lightspeed All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Pipelines All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Pipelines All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Serverless All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Serverless All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Serverless All CVEProject cvelistV5 (CNA)
Red Hat OpenShift Serverless All CVEProject cvelistV5 (CNA)
Red Hat Power monitoring for Red Hat OpenShift All CVEProject cvelistV5 (CNA)
Red Hat Red Hat 3scale API Management Platform 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Ceph Storage 5 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Ceph Storage 6 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Ceph Storage 8 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Ceph Storage 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Certification Program for Red Hat Enterprise Linux 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Connectivity Link 1 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 10 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 7 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 8 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux 9 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift AI (RHOAI) All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Cluster Manager CLI All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Container Platform 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift Virtualization 4 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift distributed tracing 3 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift for Windows Containers All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenShift on AWS All CVEProject cvelistV5 (CNA)
Red Hat Red Hat OpenStack Platform 17.1 All CVEProject cvelistV5 (CNA)
Red Hat Red Hat Satellite 6 All CVEProject cvelistV5 (CNA)
Red Hat Security Profiles Operator All CVEProject cvelistV5 (CNA)
Red Hat Zero Trust Workload Identity Manager All CVEProject cvelistV5 (CNA)
Red Hat Zero Trust Workload Identity Manager - Tech Preview All CVEProject cvelistV5 (CNA)
golang.org/x/net golang.org/x/net/idna v < 0.55.0 CVEProject cvelistV5 (CNA)

References and advisories

159
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Details

Published
2026-05-22
Last updated
2026-09-17
State
Published
Assigner (CNA)
Go

Exploit prediction (EPSS)

1.83%
Probability of exploitation in 30 days
79%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
No
Exploitation
None
Technical impact
Total

Weaknesses (CWE)

  • CWE-1289
    Improper Validation of Unsafe Equivalence in Input