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Fencer Intel
high 7.5

CVE-2026-78661 json

Avoid quadratic complexity when coalescing text nodes in html in golang.org/x/net

published 15d ago modified 7d ago also EUVD-2026-111399 , GO-2026-6860

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

When coalescing adjacent text nodes in addText and fosterParent, appending to an existing TextNode's Data via string concatenation (n.Data += text) reallocated and copied the accumulated string on every token. Inputs containing many short text runs separated by ignored end tags (such as "a</x>") caused O(n^2) allocations and byte copies. Accumulate coalesced text in per-node byte slices during parsing and materialize Data strings once at the end of parse.

Patch / fix

  • go golang.org/x/net 0.62.0
  • golang.org/x/net golang.org/x/net/html 0.62.0
  • golang-golang-x-net Debian 14 1:0.62.0-1

debian advisories DEBIAN-CVE-2026-78661

  • amazon-cloudwatch-agent openSUSE Tumbleweed 1.300074.0-1.1
  • google-osconfig-agent openSUSE Tumbleweed 20261103.02-1.1

opensuse advisories openSUSE-SU-2026:12425-1openSUSE-SU-2026:12430-1

Is CVE-2026-78661 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-78661 updated cvss 7.5

golang.org/x/net/html: golang.org/x/net/html: Denial of Service via crafted HTML input

  • Red Hat OpenShift AI (RHOAI) rhoai/rhai-cli-rhel9, rhoai/odh-trainer-rhel9, rhoai/odh-core-bff-rhel9, rhoai/odh-rhel9-operator, rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, +45 more
    affected: workaround, no fix available
  • Red Hat Ansible Automation Orchestrator 2026 ansible-automation-platform/automation-orchestrator-rhel9-operator, ansible-automation-platform/automation-orchestrator-operator-bundle 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 AWS Load Balancer Operator albo/aws-load-balancer-controller-rhel8 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-waiters-rhel10, openshift-builds/openshift-builds-webhook-rhel10, openshift-builds/openshift-builds-rhel10-operator, +12 more Red Hat cert-manager Operator for Red Hat OpenShift cert-manager/jetstack-cert-manager-rhel9, cert-manager/cert-manager-istio-csr-rhel9, cert-manager/cert-manager-trust-manager-rhel9, cert-manager/jetstack-cert-manager-acmesolver-rhel9 Red Hat Compliance Operator compliance/openshift-compliance-operator-bundle
    +33 more products
    Red Hat Confidential Compute Attestation agent-sandbox/agent-sandbox-rhel9-operator, openshift-sandboxed-containers/osc-rhel9-operator, openshift-sandboxed-containers/osc-podvm-payload-rhel9, openshift-sandboxed-containers/osc-cloud-api-adaptor-rhel9 Red Hat Cost Management On Premise costmanagement/costmanagement-ros-ocp-backend-rhel9 Red Hat Cryostat 4 cryostat/cryostat-rhel9-operator, cryostat/cryostat-grafana-dashboard-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-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-operator-bundle, lvms4/lvms-must-gather-rhel8, lvms4/lvms-must-gather-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-cli-rhel9, mta/mta-hub-rhel9, mta/mta-analyzer-addon-rhel9, mta/mta-platform-addon-rhel9, mta/mta-go-external-provider-rhel9, mta/mta-java-external-provider-rhel9, +2 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, +12 more Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-agent-rhel9, multicluster-globalhub/multicluster-globalhub-grafana-rhel9, multicluster-globalhub/multicluster-globalhub-manager-rhel9, multicluster-globalhub/multicluster-globalhub-rhel9-operator Red Hat Multicluster Global Hub 5 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 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 Red Hat Node Maintenance Operator workload-availability/node-maintenance-operator-bundle, container-native-virtualization/node-maintenance-operator Red Hat OpenShift API for Data Protection oadp/oadp-velero-rhel9, oadp/oadp-rhel9-operator, oadp/oadp-mustgather-rhel9, oadp/oadp-cli-binaries-rhel9, oadp/oadp-velero-plugin-rhel9, oadp/oadp-kubevirt-velero-plugin-rhel9, +2 more Red Hat OpenShift Developer Tools and Services helm 3.19.5.3-72.el9 Red Hat OpenShift Lightspeed openshift-lightspeed/otelcol-lightspeed-rhel9, openshift-lightspeed/lightspeed-rhel9-operator, openshift-lightspeed/openshift-mcp-server-rhel9 Red Hat OpenShift Serverless kn-workflow-plugin 1.38.1-1.el9, openshift-serverless-clients 1.17.0-4.el9, openshift-serverless-1/logic-rhel9-operator, openshift-serverless-1/kn-plugin-func-func-util-rhel9 Red Hat OpenShift Service Mesh 3 istio-proxy-selinux, istio-proxy 1.30.5-1.el9, openshift-service-mesh/kiali-rhel9, openshift-service-mesh/istio-cni-rhel9, openshift-service-mesh/istio-pilot-rhel9, openshift-service-mesh/istio-proxyv2-rhel9, +1 more Red Hat 3scale API Management Platform 2 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/prometheus-rhel9, rhacm2/acm-grafana-rhel9, rhacm2/acm-prometheus-rhel9, rhacm2/acm-must-gather-rhel9, +24 more Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-main-rhel9, advanced-cluster-security/rhacs-roxctl-rhel8, advanced-cluster-security/rhacs-roxctl-rhel9, advanced-cluster-security/rhacs-scanner-rhel8, advanced-cluster-security/rhacs-scanner-rhel9, +7 more Red Hat Ansible Automation Platform 2 receptor 1.6.9-3.el10ap, 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, rhceph/rhceph-promtail-rhel9 Red Hat Ceph Storage 9 rhceph/alloy-rhel10, rhceph/grafana-rhel10, rhceph/oauth2-proxy-rhel9, rhceph/oauth2-proxy-rhel10 Red Hat Certification Program for Red Hat Enterprise Linux 9 redhat-certification-cnf 9.0-20240522.1.el9, redhat-certification-preflight 9.43-20261016.el9 Red Hat Connectivity Link 1 rhcl-1/developer-portal-controller-rhel9 Red Hat Developer Hub 1 rhdh/rhdh-rhel9-operator
    under investigation

29 more under investigation 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
yes
Technical impact
partial
Assessed
7d ago

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go golang.org/x/net
<0.62.0
0.62.0

Affected products

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

Classification

Weakness
  • CWE-407 Inefficient Algorithmic Complexity

References

Sources

Fencer Intel 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.