Escaper bypass leads to XSS in html/template
Priority LOW 27CWE-116Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 12 fixed, 65 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
If a trusted template author were to write a <script> tag containing an empty 'type' attribute or a 'type' attribute with an ASCII whitespace, the execution of the template would incorrectly escape any data passed into the <script> block.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00371 31st percentileScored 2026-11-07
Fix Partial html/template (Go standard library): 1.25.10, 1.26.3Red Hat: 13 advisoriesRed Hat: 12 fixed, 65 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 | html/template | before 1.25.10; 1.26.0-0 to before 1.26.3 | 1.25.10, 1.26.3 | Patch available | CNA |
- html/template VendorGo standard library Affected before 1.25.10; 1.26.0-0 to before 1.26.3 Fixed in 1.25.10, 1.26.3 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* | before 1.25.10; 1.26.0 to before 1.26.3 | Vulnerable | Go standard library |
- cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* Versions before 1.25.10; 1.26.0 to before 1.26.3 Vulnerable ·Go standard library
Remediation
- Fix · CNA html/template (Go standard library) Fixed in 1.25.10, 1.26.3
Red Hat 13 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-2026:61253 Released 2026-08-31 · Red Hat rating Importantgolang security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) go-toolset-1.26.5-1.el9_2, golang-1.26.5-1.el9_2, golang-bin-1.26.5-1.el9_2 +5
Show 10 more Red Hat advisories
- RHSA-2026:57649 Released 2026-08-20 · Red Hat rating Importantgolang security update
- Red Hat Enterprise Linux AppStream E4S (v.9.4) go-toolset-1.26.5-1.el9_4, golang-1.26.5-1.el9_4, golang-bin-1.26.5-1.el9_4 +5
- 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-2026:49712 Released 2026-08-03 · Red Hat rating Importantgolang security update
- Red Hat Enterprise Linux AppStream EUS (v.9.6) go-toolset-1.26.5-1.el9_6, golang-1.26.5-1.el9_6, golang-bin-1.26.5-1.el9_6 +5
- RHSA-2026:49702 Released 2026-08-03 · Red Hat rating Importantgolang security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) go-toolset-1.26.5-1.el10_0, golang-1.26.5-1.el10_0, golang-bin-1.26.5-1.el10_0 +5
- 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-2026:23264 Released 2026-06-04 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images golang1.26-1.26.4-2.hum1@aarch64, golang1.26-1.26.4-2.hum1@src, golang1.26-1.26.4-2.hum1@x86_64 +10
- RHSA-2026:23262 Released 2026-06-04 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images golang1.25-1.25.11-2.hum1@aarch64, golang1.25-1.25.11-2.hum1@src, golang1.25-1.25.11-2.hum1@x86_64 +10
- RHSA-2026:22112 Released 2026-06-01 · Red Hat rating Importantgo-toolset:rhel8 security update
- Red Hat Enterprise Linux AppStream (v. 8) delve-1.25.2-1.module+el8.10.0+23746+9db33b5e.aarch64::go-toolset:rhel8, delve-1.25.2-1.module+el8.10.0+23746+9db33b5e.ppc64le::go-toolset:rhel8, delve-1.25.2-1.module+el8.10.0+23746+9db33b5e.src::go-toolset:rhel8 +22
- RHSA-2026:22121 Released 2026-06-01 · Red Hat rating Importantgolang security update
- Red Hat Enterprise Linux AppStream (v. 9) go-toolset-1.26.3-1.el9_8, golang-1.26.3-1.el9_8, golang-bin-1.26.3-1.el9_8 +5
- RHSA-2026:22120 Released 2026-06-01 · Red Hat rating Importantgolang security update
- Red Hat Enterprise Linux AppStream (v. 10) go-toolset-1.26.3-4.el10_2, golang-1.26.3-4.el10_2, golang-bin-1.26.3-4.el10_2 +5
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Go standard library html/template 1.25.10, 1.26.3
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-28705 Bypass of meta content URL escaping causes XSS in html/templatePriority 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 |
| Compliance Operator | Affected | No fix yet: Fix deferred |
| Confidential Compute Attestation | Affected | No fix yet: Fix deferred |
| Cryostat 4 | Affected | No fix yet: Fix deferred |
| Custom Metric Autoscaler operator for Red Hat Openshift | Affected | No fix yet: Fix deferred |
| Deployment Validation Operator | Affected | No fix yet: Fix deferred |
| External Secrets Operator for Red Hat OpenShift | 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 |
| OpenShift Developer Tools and Services | Affected | No fix yet: Fix deferred |
| OpenShift Lightspeed | 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 2 | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Power monitoring for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Red Hat 3scale API Management Platform 2 | Affected | No fix yet: Fix deferred |
| 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 6 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
| Red Hat Certification Program for Red Hat Enterprise Linux 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 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | 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 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 OpenShift on AWS | 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 1 | Affected | No fix yet: Fix deferred |
| Red Hat Service Interconnect 2 | Affected | No fix yet: Fix deferred |
| 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 |
| OpenShift API for Data Protection 1.6 | Fixed | RHSA-2026:43692 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:22120 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:22112 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:22121 |
| Red Hat Enterprise Linux AppStream E4S (v.9.2) | Fixed | RHSA-2026:61253 |
| Red Hat Enterprise Linux AppStream E4S (v.9.4) | Fixed | RHSA-2026:57649 |
| Red Hat Enterprise Linux AppStream EUS (v. 10.0) | Fixed | RHSA-2026:49702 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:49712 |
| Red Hat Hardened Images | Fixed | RHSA-2026:23262, RHSA-2026:23264 |
| Red Hat OpenShift AI 3.4 | Fixed | RHSA-2026:91248 |
| Red Hat OpenShift AI 3.5 | Fixed | RHSA-2026:91249 |
| multicluster engine for Kubernetes 2.11 | Fixed | RHSA-2026:57194 |
Not affected: 3 products
- OpenShift API for Data Protection 1.6
- Red Hat OpenShift Container Platform 4
- multicluster engine for Kubernetes 2.11
Timeline
- 2026-10-02 Threatist record created from CVE-2026-39826
- 2026-10-03 Alias added: GHSA-3v2c-x6q9-f697
- 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
References
More Go standard library Go vulnerabilities
- TI-2020-00578 Improper certificate validation in Microsoft Windows KEVCVSS 3.1HIGH 8.1
- TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
- TI-2018-05208 The "go get" implementation in Go 1.9.4, when the -insecure command-line option is used… CVSS 3.1HIGH 8.8
- TI-2018-12083 Improper input validation in [UNKNOWN] golang CVSS 3.1HIGH 8.1
- TI-2024-16306 Mishandling of corrupt central directory record in archive/zip CVSS 3.1MEDIUM 5.5
- TI-2021-15910 Go before 1.16.9 and 1.17.x before 1.17.2 has a Buffer Overflow via large arguments in a… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-39826 · CVE Program
- CVE-2026-39826 · NVD
- FIRST EPSS
- GHSA-3v2c-x6q9-f697 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-39826 · 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