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Fencer Vulns
medium 6.1

CVE-2026-42502 json

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

published 2026-05-22 5 mo ago modified 2026-09-22 48 d ago also EUVD-2026-31448 , GO-2026-5027

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 13%
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-2026-42502

  • osbuild-composer RHEL 9 165.1-5.el9_8
  • osbuild-composer-core RHEL 9 165.1-5.el9_8
  • osbuild-composer-worker RHEL 9 165.1-5.el9_8
  • golang1.27 hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-bin hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-src hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-misc hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-tests hummingbird 1 1.27.1-0.1.hum1

red hat advisories RHSA-2026:69293RHSA-2026:66561RHSA-2026:62391RHSA-2026:67517RHSA-2026:67138RHSA-2026:67139

  • 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

  • percona-toolkit openSUSE Tumbleweed 3.7.1.4-1.1
  • 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

opensuse advisories openSUSE-SU-2026:12166-1openSUSE-SU-2026:21824-1openSUSE-SU-2026:21662-1openSUSE-SU-2026:21590-1openSUSE-SU-2026:21483-1openSUSE-SU-2026:21436-1

  • osbuild-composer AlmaLinux 9 165.1-5.el9_8.alma.1
  • osbuild-composer-core AlmaLinux 9 165.1-5.el9_8.alma.1
  • osbuild-composer-worker AlmaLinux 9 165.1-5.el9_8.alma.1
  • osbuild-composer AlmaLinux 10 165.1-5.el10_2.alma.1
  • osbuild-composer-core AlmaLinux 10 165.1-5.el10_2.alma.1
  • osbuild-composer-worker AlmaLinux 10 165.1-5.el10_2.alma.1

almalinux advisories ALSA-2026:69293ALSA-2026:66432

  • osbuild-composer Rocky Linux 9 165.1-5.el9_8.rocky.0.1
  • image-builder Rocky Linux 9 52.1-2.el9_8
  • image-builder Rocky Linux 10 52.1-2.el10_2.rocky.0.1
  • osbuild-composer Rocky Linux 10 165.1-5.el10_2.rocky.0.1

rocky linux advisories RLSA-2026:69293RLSA-2026:67138RLSA-2026:67139RLSA-2026:66432

  • 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 8.7.11-7
  • cloud-provider-kubevirt Azure Linux 3.0 0.5.1-5
  • cni-plugins Azure Linux 3.0 1.4.0-6
  • containerd2 Azure Linux 3.0 2.2.4-4
  • 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-87372AZL-87420AZL-87456AZL-87489AZL-87519AZL-87531

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-2026-42502 updated cvss 6.1

golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via unexpected HTML tree rendering

  • 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-trust-manager-rhel9 Red Hat Compliance Operator compliance/openshift-compliance-operator-bundle 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 Red Hat Cryostat 4 cryostat/cryostat-rhel9-operator, cryostat/cryostat-grafana-dashboard-rhel9
    +1 more products
    Red Hat External Secrets Operator for Red Hat OpenShift external-secrets-operator/external-secrets-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Fence Agents Remediation Operator workload-availability/fence-agents-remediation-rhel8-operator, workload-availability/fence-agents-remediation-operator-bundle
    affected: workaround, no fix available
  • Red Hat File Integrity Operator compliance/openshift-compliance-operator-bundle, compliance/openshift-file-integrity-operator-bundle Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9-operator Red Hat Logical Volume Manager Storage lvms4/lvms-rhel8-operator, lvms4/lvms-rhel9-operator, lvms4/lvms-must-gather-rhel8 Red Hat Migration Toolkit for Applications 8 mta/mta-hub-rhel8, mta/mta-hub-rhel9, mta/mta-solution-server-rhel9, mta/mta-dotnet-external-provider-rhel8 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
    +2 more products
    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, +12 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
    affected: workaround, no fix available “Fix deferred”
  • 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
    affected: workaround, no fix available
  • Red Hat OpenShift Developer Tools and Services helm Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-rhel9-operator Red Hat OpenShift Pipelines openshift-pipelines-client
    affected: workaround, no fix available “Fix deferred”
  • 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
    affected: workaround, no fix available
  • 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/volsync-rhel9, rhacm2/prometheus-rhel9, rhacm2/acm-must-gather-rhel9, rhacm2/multiclusterhub-rhel9, rhacm2/search-collector-rhel9, rhacm2/submariner-addon-rhel9, +7 more Red Hat Ansible Automation Platform 2 receptor, 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
    +9 more products
    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, podman-docker, podman-remote, podman-gvproxy, +6 more Red Hat Enterprise Linux 10 podman, grafana, gvisor-tap-vsock, opentelemetry-collector Red Hat Hardened Images golang1.25
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/rhai-cli-rhel9 Red Hat OpenShift Cluster Manager CLI ocm-cli-clients/ocm-cli-rhel9
    affected: workaround, no fix available
show 1 more
  • Red Hat OpenShift Container Platform 4 cri-o, podman, cri-tools, openshift, podman-tests, podman-docker, +214 more Red Hat OpenShift Container Platform 5 cri-o, podman, cri-tools, openshift, microshift, openshift-clients, +114 more
    affected: workaround, no fix available “Fix deferred”

16 more affected, 50 more fixed, 43 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

0.22% chance of exploitation in the next 30 days, higher than 13% 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-1021 Improper Restriction of Rendered UI Layers or Frames

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.