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Fencer Vulns
medium 6.1

CVE-2026-42506 json

Invoking incorrect handling of namespaced elements in foreign content in golang.org/x/net/html

published 2026-05-22 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-31446 , GO-2026-5025

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.

Patch / fix

  • go golang.org/x/net 0.55.0
  • golang.org/x/net golang.org/x/net/html 0.55.0
  • golang-golang-x-net Debian 14 1:0.55.0-1

debian advisories DEBIAN-CVE-2026-42506

  • containerized-data-importer SLE Module for Containers 15 SP7 1.64.0-150700.9.14.1
  • grafana SLE Module for Package Hub 15 SP7 12.4.5-150200.3.91.1
  • kubevirt-1.6 SLE Module for Containers 15 SP7 1.6.6-150700.15.17.1
  • kubevirt SLE Module for Containers 15 SP7 1.7.4-150700.3.30.1
  • terraform-provider-aws SLE Module for Public Cloud 15 SP5, SLE Module for Public Cloud 15 SP4 3.11.0-150200.6.18.1
  • terraform-provider-tls SLE Module for Public Cloud 15 SP5, SLE Module for Public Cloud 15 SP4 3.0.0-150200.5.15.1
  • terraform-provider-helm SLE Module for Public Cloud 15 SP5, SLE Module for Public Cloud 15 SP4 2.9.0-150200.6.23.1
  • terraform-provider-null SLE Module for Public Cloud 15 SP5, SLE Module for Public Cloud 15 SP4 3.0.0-150200.6.18.1

suse advisories SUSE-SU-2026:4209-1SUSE-SU-2026:3718-1SUSE-SU-2026:3630-1SUSE-SU-2026:3203-1SUSE-SU-2026:3056-1SUSE-SU-2026:22613-1

  • containerized-data-importer1.65 openSUSE Leap 16.0 1.65.0-160000.3.1
  • glab openSUSE Leap 16.0 1.114.0-bp160.1.1
  • kubevirt1.8 openSUSE Leap 16.0 1.8.4-160000.1.1
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • rclone openSUSE Leap 16.0 1.74.4-bp160.1.1
  • lux openSUSE Leap 16.0 0.24.1-bp160.1.1
  • gomuks openSUSE Tumbleweed 26.03+git.1780250926.564a8707-1.1
  • cosign openSUSE Leap 16.0 3.1.1-160000.1.1

opensuse advisories openSUSE-SU-2026:21824-1openSUSE-SU-2026:21662-1openSUSE-SU-2026:21590-1openSUSE-SU-2026:21483-1openSUSE-SU-2026:21436-1openSUSE-SU-2026:21367-1

  • application-gateway-kubernetes-ingress Azure Linux 3.0 1.7.7-5
  • cert-manager Azure Linux 3.0 1.12.15-9
  • cf-cli Azure Linux 3.0 8.7.11-6
  • cloud-provider-kubevirt Azure Linux 3.0 0.5.1-4
  • cni-plugins Azure Linux 3.0 1.4.0-6
  • containerd2 Azure Linux 3.0 2.2.4-2
  • containerized-data-importer Azure Linux 3.0 1.62.0-6
  • cri-tools Azure Linux 3.0 1.32.0-6

azure linux advisories AZL-87363AZL-87432AZL-87477AZL-87483AZL-87504AZL-87528

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42506 updated cvss 5.4

golang.org/x/net/html: golang.org/x/net/html: Cross-Site Scripting (XSS) via arbitrary HTML parsing

  • Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 rhai/assisted-installer-rhel9, rhai/assisted-installer-agent-rhel9, rhai/assisted-installer-controller-rhel9, assisted/agent-preinstall-image-builder-rhel9 Red Hat Builds for Red Hat OpenShift openshift-builds/openshift-builds-waiters-rhel9, openshift-builds/openshift-builds-webhook-rhel9, openshift-builds/openshift-builds-rhel9-operator, openshift-builds/openshift-builds-controller-rhel9, openshift-builds/openshift-builds-git-cloner-rhel9, openshift-builds/openshift-builds-image-bundler-rhel9, +3 more Red Hat cert-manager Operator for Red Hat OpenShift cert-manager/cert-manager-istio-csr-rhel9, cert-manager/cert-manager-trust-manager-rhel9 Red Hat Confidential Compute Attestation openshift-sandboxed-containers/osc-rhel9-operator, openshift-sandboxed-containers/osc-podvm-payload-rhel9, openshift-sandboxed-containers/osc-cloud-api-adaptor-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Cryostat 4 cryostat/cryostat-storage-rhel9, cryostat/cryostat-rhel9-operator, cryostat/cryostat-grafana-dashboard-rhel9
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat External Secrets Operator for Red Hat OpenShift external-secrets-operator/external-secrets-rhel9 Red Hat Fence Agents Remediation Operator workload-availability/fence-agents-remediation-rhel8-operator, workload-availability/fence-agents-remediation-operator-bundle Red Hat File Integrity Operator compliance/openshift-compliance-operator-bundle, compliance/openshift-file-integrity-rhel8-operator, compliance/openshift-file-integrity-operator-bundle Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9-operator Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/logging-loki-rhel9, openshift-logging/cluster-logging-rhel9-operator Red Hat Logical Volume Manager Storage lvms4/lvms-rhel8-operator, lvms4/lvms-rhel9-operator, lvms4/lvms-must-gather-rhel8, lvms4/lvms-must-gather-rhel9
    +29 more products
    Red Hat Migration Toolkit for Applications 8 mta/mta-cli-rhel9, mta/mta-hub-rhel8, mta/mta-hub-rhel9, mta/mta-analyzer-addon-rhel9, mta/mta-platform-addon-rhel9, mta/mta-discovery-addon-rhel9, +5 more Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-controller-rhel8 Red Hat Multiarch Tuning Operator multiarch-tuning/multiarch-tuning-rhel9-operator, multiarch-tuning/multiarch-tuning-operator-bundle Red Hat Multicluster Engine for Kubernetes multicluster-engine/maestro-rhel9, multicluster-engine/discovery-rhel9, multicluster-engine/assisted-installer-rhel8, multicluster-engine/assisted-installer-rhel9, multicluster-engine/assisted-service-8-rhel8, multicluster-engine/assisted-service-9-rhel9, +11 more Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-agent-rhel8, multicluster-globalhub/multicluster-globalhub-agent-rhel9, multicluster-globalhub/multicluster-globalhub-grafana-rhel8, multicluster-globalhub/multicluster-globalhub-grafana-rhel9, multicluster-globalhub/multicluster-globalhub-manager-rhel8, multicluster-globalhub/multicluster-globalhub-manager-rhel9, +3 more Red Hat Network Observability Operator network-observability/network-observability-cli-rhel9, network-observability/network-observability-rhel9-operator, network-observability/network-observability-ebpf-agent-rhel9, network-observability/network-observability-flowlogs-pipeline-rhel9 Red Hat Node HealthCheck Operator workload-availability/node-healthcheck-rhel8-operator, workload-availability/node-healthcheck-operator-bundle, node-healthcheck-operator-tech-preview/node-healthcheck-operator-rhel8, node-healthcheck-operator-tech-preview/node-healthcheck-rhel8-operator, node-healthcheck-operator-tech-preview/node-healthcheck-operator-bundle Red Hat OpenShift API for Data Protection oadp/oadp-rhel9-operator, oadp/oadp-mustgather-rhel9, oadp/oadp-kubevirt-velero-plugin-rhel9, oadp/oadp-velero-restic-restore-helper-rhel9 Red Hat OpenShift Developer Tools and Services helm Red Hat OpenShift Lightspeed openshift-lightspeed/openshift-mcp-server-rhel9 Red Hat OpenShift Pipelines openshift-pipelines-client Red Hat OpenShift Serverless kn-workflow-plugin, openshift-serverless-clients, openshift-serverless-1/logic-rhel9-operator, openshift-serverless-1/kn-plugin-func-func-util-rhel9 Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/istio-cni-rhel9, openshift-service-mesh/istio-pilot-rhel9, openshift-service-mesh/istio-proxyv2-rhel9, openshift-service-mesh/istio-rhel9-operator Red Hat 3scale API Management Platform 2 3scale-amp2/3scale-rhel7-operator, 3scale-amp2/3scale-rhel9-operator, 3scale-amp2/3scale-operator-bundle Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/subctl-rhel9, rhacm2/volsync-rhel9, rhacm2/acm-grafana-rhel9, rhacm2/acm-prometheus-rhel9, rhacm2/acm-must-gather-rhel9, rhacm2/multiclusterhub-rhel9, +23 more Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel9, advanced-cluster-security/rhacs-roxctl-rhel9, advanced-cluster-security/rhacs-scanner-rhel8, advanced-cluster-security/rhacs-scanner-rhel9, advanced-cluster-security/rhacs-rhel8-operator, advanced-cluster-security/rhacs-rhel9-operator, +5 more Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/receptor-rhel9, ansible-automation-platform-27/receptor-rhel9 Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 7 rhceph/grafana-rhel9 Red Hat Ceph Storage 8 rhceph/grafana-rhel9, rhceph/oauth2-proxy-rhel9 Red Hat Ceph Storage 9 rhceph/alloy-rhel10, rhceph/grafana-rhel10, rhceph/oauth2-proxy-rhel9, rhceph/oauth2-proxy-rhel10 Red Hat Connectivity Link 1 rhcl-1/developer-portal-controller-rhel9 Red Hat Developer Hub 1 rhdh/rhdh-rhel9-operator Red Hat Edge Manager 1 flightctl, rhem/flightctl-api-rhel9, rhem/flightctl-api-rhel10, rhem/flightctl-worker-rhel9, rhem/flightctl-worker-rhel10, rhem/flightctl-db-setup-rhel9, +19 more Red Hat Enterprise Linux 8 podman, podman-tests, podman-docker, podman-remote, podman-gvproxy, podman-plugins, +6 more Red Hat Enterprise Linux 9 podman, grafana, podman-tests, image-builder, podman-docker, podman-remote, +11 more Red Hat Enterprise Linux 10 podman, grafana, image-builder, gvisor-tap-vsock, osbuild-composer, opentelemetry-collector Red Hat Lightspeed for Runtimes Operator rh-lightspeed-runtimes/runtimes-inventory-rhel9-operator Red Hat OpenShift AI (RHOAI) rhoai/rhai-cli-rhel9, rhoai/odh-trainer-rhel9, rhoai/odh-maas-api-rhel9, rhoai/odh-rhel9-operator, rhoai/odh-feast-operator-rhel9, rhoai/odh-kube-auth-proxy-rhel9, +17 more
    affected: workaround, no fix available “Fix deferred”

20 more affected, 7 more fixed, 14 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go golang.org/x/net
<0.55.0
0.55.0

Affected products

  • golang.org/x/net golang.org/x/net/html

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.