Invoking denial of service when parsing arbitrary HTML in golang.org/x/net/html
Priority LOW 29CWE-400Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 7 fixed, 57 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.
Summary
Parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00326 25th percentileScored 2026-11-07
Fix Partial golang.org/x/net/html (golang.org/x/net): 0.55.0golang.org/x/net (Go): 0.55.0Red Hat: 8 advisoriesRed Hat: 7 fixed, 57 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Go standard library | golang.org/x/net/html | before 0.55.0 | 0.55.0 | Patch available | CNA |
| — | golang.org/x/net (Go) | before 0.55.0 | 0.55.0 | Patch available | GHSA-5cv4-jp36-h3mw |
- golang.org/x/net/html VendorGo standard library Affected before 0.55.0 Fixed in 0.55.0 Patch available CNA
- golang.org/x/net (Go) Vendor— Affected before 0.55.0 Fixed in 0.55.0 Patch available GHSA-5cv4-jp36-h3mw
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:golang:net:*:*:*:*:*:go:*:* | before 0.55.0 | Vulnerable | Go standard library |
- cpe:2.3:a:golang:net:*:*:*:*:*:go:*:* Versions before 0.55.0 Vulnerable ·Go standard library
Remediation
- Fix · CNA golang.org/x/net/html (golang.org/x/net) Fixed in 0.55.0
- Fix · GHSA-5cv4-jp36-h3mw golang.org/x/net (Go) Fixed in 0.55.0 Advisory →
Red Hat 8 advisories
- RHSA-2026:91249 Released 2026-10-27 · Red Hat rating CriticalRed Hat AI Base Images 3.5.5 (Neuron)
- Red Hat OpenShift AI 3.5 registry.redhat.io/rhai/base-image-neuron-rhel9
- RHSA-2026:91248 Released 2026-10-27 · Red Hat rating CriticalRed Hat AI Base Images 3.4.6 (Neuron)
- Red Hat OpenShift AI 3.4 registry.redhat.io/rhai/base-image-neuron-rhel9
- RHSA-2026:82322 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.17.2
- Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/cert-manager-operator-rhel9
Show 5 more Red Hat advisories
- RHSA-2026:82304 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.17.2
- Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9, registry.redhat.io/cert-manager/jetstack-cert-manager-rhel9
- RHSA-2026:57194 Released 2026-08-19 · Red Hat rating Importantmulticluster engine for Kubernetes v2.11.5 security update
- multicluster engine for Kubernetes 2.11 registry.redhat.io/multicluster-engine/addon-manager-rhel9, registry.redhat.io/multicluster-engine/backplane-rhel9-operator, registry.redhat.io/multicluster-engine/cluster-api-provider-kubevirt-rhel9 +11
- RHSA-2026:43692 Released 2026-07-22 · Red Hat rating ImportantRed Hat OpenShift API for Data Protection
- OpenShift API for Data Protection 1.6 registry.redhat.io/oadp/oadp-velero-rhel9
- RHSA-2026:37387 Released 2026-07-09 · Red Hat rating ImportantRed Hat OpenShift Data Foundation 4.22.0 security, enhancement & bug fix update
- Red Hat Openshift Data Foundation 4.22 registry.redhat.io/odf4/cephcsi-rhel9, registry.redhat.io/odf4/cephcsi-rhel9-operator, registry.redhat.io/odf4/devicefinder-rhel9 +24
- RHSA-2026:34342 Released 2026-07-01 · Red Hat rating CriticalCluster Observability Operator 1.5.0
- Cluster Observability Operator 1.5 registry.redhat.io/cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9, registry.redhat.io/cluster-observability-operator/distributed-tracing-console-plugin-pf5-rhel9, registry.redhat.io/cluster-observability-operator/distributed-tracing-console-plugin-pf6-rhel9 +9
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
golang.org/x/net/html 0.55.0
5 records Highest priority Priority LOW 5 LOW
Other records, highest priority first
- TI-2026-30789 Invoking incorrect handling of namespaced elements in foreign content in golang.org/x/net/htmlPriority LOW 27
- TI-2026-30785 Invoking incorrect handling of HTML elements in foreign content in golang.org/x/net/htmlPriority LOW 27
- TI-2026-21586 Invoking duplicate attributes can cause XSS in golang.org/x/net/htmlPriority LOW 27
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Assisted Installer for Red Hat OpenShift Container Platform 2 | Affected | No fix yet: Fix deferred |
| Builds for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Confidential Compute Attestation | Affected | No fix yet: Fix deferred |
| Cryostat 4 | Affected | No fix yet: Fix deferred |
| External Secrets Operator for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Fence Agents Remediation Operator | Affected | No fix yet: Fix deferred |
| File Integrity Operator | Affected | No fix yet: Fix deferred |
| Gatekeeper 3 | Affected | No fix yet: Fix deferred |
| Logging Subsystem for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Logical Volume Manager Storage | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 8 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Containers | Affected | No fix yet: Fix deferred |
| Multiarch Tuning Operator | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| Multicluster Global Hub | Affected | No fix yet: Fix deferred |
| Network Observability Operator | Affected | No fix yet: Fix deferred |
| Node HealthCheck Operator | Affected | No fix yet: Fix deferred |
| OpenShift API for Data Protection | Affected | No fix yet: Fix deferred |
| OpenShift Pipelines | Affected | No fix yet: Fix deferred |
| OpenShift Serverless | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Red Hat 3scale API Management Platform 2 | Affected | No fix planned: Out of support scope |
| Red Hat Advanced Cluster Management for Kubernetes 2 | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Security 4 | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 5 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 7 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 8 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
| Red Hat Connectivity Link 1 | Affected | No fix yet: Fix deferred |
| Red Hat Developer Hub 1 | Affected | No fix yet: Fix deferred |
| Red Hat Edge Manager 1 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Lightspeed for Runtimes Operator | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Cluster Manager CLI | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Workspaces Operator | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift GitOps | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Virtualization 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift distributed tracing 3 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift for Windows Containers | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 16.2 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 17.1 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet: Fix deferred |
| Red Hat Openshift Data Foundation 4 | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| Red Hat Service Interconnect 2 | Affected | No fix planned: Out of support scope |
| Red Hat Trusted Artifact Signer | Affected | No fix yet: Fix deferred |
| Security Profiles Operator | Affected | No fix yet: Fix deferred |
| Zero Trust Workload Identity Manager | Affected | No fix yet: Fix deferred |
| Zero Trust Workload Identity Manager - Tech Preview | Affected | No fix yet: Fix deferred |
| cert-manager Operator for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Cert Manager support for Red Hat OpenShift release 1.17 | Fixed | RHSA-2026:82304, RHSA-2026:82322 |
| Cluster Observability Operator 1.5 | Fixed | RHSA-2026:34342 |
| OpenShift API for Data Protection 1.6 | Fixed | RHSA-2026:43692 |
| Red Hat OpenShift AI 3.4 | Fixed | RHSA-2026:91248 |
| Red Hat OpenShift AI 3.5 | Fixed | RHSA-2026:91249 |
| Red Hat Openshift Data Foundation 4.22 | Fixed | RHSA-2026:37387 |
| multicluster engine for Kubernetes 2.11 | Fixed | RHSA-2026:57194 |
Not affected: 20 products
- Cluster Observability Operator 1.5
- Compliance Operator
- Multicluster Engine for Kubernetes
- OpenShift API for Data Protection 1.6
- OpenShift Developer Tools and Services
- OpenShift Lightspeed
- Red Hat Advanced Cluster Management for Kubernetes 2
- Red Hat Advanced Cluster Security 4
- Red Hat Ansible Automation Platform 2
- Red Hat Edge Manager 1
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
- Red Hat OpenShift Virtualization 4
- Red Hat OpenShift distributed tracing 3
- Red Hat OpenShift on AWS
- Red Hat Openshift Data Foundation 4.22
- multicluster engine for Kubernetes 2.11
Timeline
- 2026-10-02 Threatist record created from CVE-2026-25680
- 2026-10-03 Alias added: GHSA-5cv4-jp36-h3mw
- 2026-10-14 Fix available: RHSA-2026:82304 · Red Hat
- 2026-10-14 Fix available: RHSA-2026:82322 · Red Hat
- 2026-10-15 Fix available: Cert Manager support for Red Hat OpenShift release 1.17 · Red Hat
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-30 Fix available: RHSA-2026:91248 · Red Hat
- 2026-10-30 Fix available: RHSA-2026:91249 · Red Hat
- 2026-10-30 Fix available: Red Hat OpenShift AI 3.4, Red Hat OpenShift AI 3.5 · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-06 Fix available: Cluster Observability Operator 1.5 · Red Hat
References
More Go standard library Net vulnerabilities
- TI-2026-28703 Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna CVSS 3.1CRITICAL 9.6
- TI-2018-12685 The html package (aka x/net/html) through 2018-09-25 in Go mishandles… CVSS 3.1HIGH 7.5
- TI-2018-12250 The html package (aka x/net/html) through 2018-09-17 in Go mishandles… CVSS 3.1HIGH 7.5
- TI-2018-12206 The html package (aka x/net/html) before 2018-07-13 in Go mishandles "in frameset"… CVSS 3.1HIGH 7.5
- TI-2018-12687 The html package (aka x/net/html) through 2018-09-25 in Go mishandles… CVSS 3.1HIGH 7.5
- TI-2018-12686 The html package (aka x/net/html) through 2018-09-25 in Go mishandles… CVSS 3.1HIGH 7.5
Sources
- CVE-2026-25680 · CVE Program
- CVE-2026-25680 · NVD
- FIRST EPSS
- GHSA-5cv4-jp36-h3mw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-25680 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences