CVE-2026-39826 json
Escaper bypass leads to XSS in html/template
published 2026-05-07 6 mo ago modified 2026-10-26 13 d ago also BIT-golang-2026-39826 , EUVD-2026-28426 , GO-2026-4980
- cvss
- 6.1
- 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 31%
- public exploits
- 0
- none known
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.
Patch / fix
- bitnami golang 1.25.10, 1.26.3
- go stdlib 1.25.10, 1.26.3
- Go standard library html/template 1.25.10, 1.26.3
- golang-1.26 Debian 14 1.26.3-1
debian advisories DEBIAN-CVE-2026-39826
- golang RHEL 9 1.26.3-1.el9_8
- go-toolset RHEL 9 1.26.3-1.el9_8
- golang-bin RHEL 9 1.26.3-1.el9_8
- golang-src RHEL 9 1.26.3-1.el9_8
- golang-misc RHEL 9 1.26.3-1.el9_8
- golang-race RHEL 9 1.26.3-1.el9_8
- golang-tests RHEL 9 1.26.3-1.el9_8
- delve RHEL 8 1.25.2-1.module+el8.10.0+23746+9db33b5e
red hat advisories RHSA-2026:61253RHSA-2026:57649RHSA-2026:49712RHSA-2026:49702RHSA-2026:22121RHSA-2026:22112
- go1.25-openssl SLES for SAP applications 16.0, SLES 16.0 1.25.12-160000.1.1
- go1.26-openssl SLES for SAP applications 16.0, SLES 16.0 1.26.4-160000.1.1
suse advisories SUSE-SU-2026:22638-1SUSE-SU-2026:22572-1
- govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
- go1.25-openssl openSUSE Leap 16.0 1.25.12-160000.1.1
- go1.26-openssl openSUSE Leap 16.0 1.26.4-160000.1.1
- go1.26 openSUSE Tumbleweed 1.26.3-1.1
- go1.25 openSUSE Tumbleweed 1.25.10-1.1
opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:21319-1openSUSE-SU-2026:21254-1openSUSE-SU-2026:10741-1openSUSE-SU-2026:10723-1
- delve AlmaLinux 8 1.25.2-1.module_el8.10.0+4074+24330916
- golang AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
- go-toolset AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
- golang-bin AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
- golang-src AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
- golang-misc AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
- golang-race AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
- golang-tests AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
almalinux advisories ALSA-2026:22112ALSA-2026:22121
- golang Rocky Linux 10 1.26.3-4.el10_2
- golang Rocky Linux 9 1.26.3-1.el9_8
- delve Rocky Linux 8 1.25.2-1.module+el8.10.0+40035+ee0a7047
- golang Rocky Linux 8 1.25.10-1.module+el8.10.0+40200+0fd0f175
rocky linux advisories RLSA-2026:22120RLSA-2026:22121RLSA-2026:22112
- go Alpine 3.23 1.25.10-r0
- go Alpine 3.24 1.26.3-r0
- rclone Alpine 3.24 1.74.1-r0
alpine advisories ALPINE-CVE-2026-39826
Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- go.dev/issue/78981 patch
- go.dev/cl/771180 patch
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-2026-39826 updated cvss 5.4
html/template: golang: html/template: Cross-site scripting due to incorrect script tag escaping
-
Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 rhai/assisted-installer-rhel9 Red Hat Builds for Red Hat OpenShift openshift-builds/openshift-builds-waiters-rhel9 Red Hat cert-manager Operator for Red Hat OpenShift cert-manager/jetstack-cert-manager-rhel9 Red Hat Compliance Operator compliance/openshift-compliance-operator-bundle Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9-operator, openshift-sandboxed-containers/osc-monitor-rhel9, confidential-compute-attestation-tech-preview/trustee-rhel9-operator Red Hat Cryostat 4 cryostat/cryostat-storage-rhel9affected: workaround, no fix available “Fix deferred”
+34 more productsfewer
Red Hat Custom Metric Autoscaler operator for Red Hat Openshift custom-metrics-autoscaler/custom-metrics-autoscaler-rhel9 Red Hat Deployment Validation Operator dvo/deployment-validation-rhel8-operator Red Hat External Secrets Operator for Red Hat OpenShift external-secrets-operator/external-secrets-rhel9 Red Hat File Integrity Operator compliance/openshift-compliance-operator-bundle Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9-operator Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/eventrouter-rhel9, openshift-logging/logging-loki-rhel9 Red Hat Logical Volume Manager Storage lvms4/topolvm-rhel8, lvms4/topolvm-rhel9, lvms4/lvms-rhel9-operator Red Hat Migration Toolkit for Applications 8 mta/mta-cli-rhel9 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-controller-rhel8 Red Hat Multiarch Tuning Operator multiarch-tuning/multiarch-tuning-rhel9-operator Red Hat Multicluster Engine for Kubernetes multicluster-engine/work-rhel9, multicluster-engine/maestro-rhel9, multicluster-engine/discovery-rhel9, multicluster-engine/placement-rhel9, multicluster-engine/addon-manager-rhel9, multicluster-engine/multicloud-manager-rhel9, +3 more Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-agent-rhel8, multicluster-globalhub/multicluster-globalhub-agent-rhel9 Red Hat Network Observability Operator network-observability/network-observability-cli-rhel9 Red Hat OpenShift Developer Tools and Services helm Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-rhel9-operator Red Hat OpenShift Pipelines openshift-pipelines-client Red Hat OpenShift Serverless kn-workflow-plugin, openshift-serverless-clients, openshift-serverless-1/kn-plugin-event-sender-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/kiali-rhel8 Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9 Red Hat Power monitoring for Red Hat OpenShift openshift-power-monitoring/kepler-rhel9 Red Hat 3scale API Management Platform 2 3scale-amp2/3scale-rhel7-operator, 3scale-amp2/3scale-rhel9-operator Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/subctl-rhel9, rhacm2/config-policy-controller-rhel9, rhacm2/klusterlet-addon-controller-rhel9, rhacm2/governance-policy-propagator-rhel9, rhacm2/acm-governance-policy-framework-addon-rhel9, rhacm2/acm-governance-policy-addon-controller-rhel9 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8 Red Hat Ansible Automation Platform 2 receptor, automation-gateway-proxy, automation-gateway-proxy-openssl30, automation-gateway-proxy-openssl32, ansible-automation-platform-26/receptor-rhel9 Red Hat Ceph Storage 5 rhceph/snmp-notifier-rhel8 Red Hat Ceph Storage 6 rhceph/snmp-notifier-rhel9 Red Hat Ceph Storage 9 rhceph/alloy-rhel10 Red Hat Certification Program for Red Hat Enterprise Linux 9 redhat-certification-preflight Red Hat Connectivity Link 1 rhcl-1/rhcl-operator-bundle Red Hat Developer Hub 1 rhdh/rhdh-rhel9-operator Red Hat Edge Manager 1 flightctl, rhem/flightctl-api-rhel9 Red Hat Enterprise Linux 7 rhc, rhc-worker-script Red Hat Enterprise Linux 8 rhc, conmon, podman, skopeo, buildah, grafana, +31 more Red Hat Enterprise Linux 9 rhc, conmon, podman, skopeo, buildah, grafana, +28 more
25 more affected, 12 more fixed, 3 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
- 6 mo ago
Exploit prediction
0.37% chance of exploitation in the next 30 days, higher than 31% 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 |
| OSV | 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 |
|---|---|---|---|
| bitnami | golang | <1.25.10 >=1.26.0-0, <1.26.3 |
1.25.10 1.26.3 |
| go | stdlib | <1.25.10 >=1.26.0-0, <1.26.3 |
1.25.10 1.26.3 |
Affected products
- Go standard library html/template
Classification
- Weakness
-
- CWE-116 Improper Encoding or Escaping of Output
References
-
go.dev
/issue/78981
patch, report
-
go.dev
/cl/771180
patch
-
pkg.go.dev
/vuln/GO-2026-4980
vendor-advisory, advisory
-
groups.google.com
/g/golang-announce/c/qcCIEXso47M
release-notes, article, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-39826
web
Sources
- CVE List CVE-2026-39826
- NVD CVE-2026-39826
- OSV BIT-golang-2026-39826
- OSV GO-2026-4980
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.