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Fencer Vulns
medium 5.3

CVE-2026-6993 json

go-kratos http.DefaultServeMux Fallback server.go NewServer confused deputy

published 2026-04-25 6 mo ago modified 2026-10-26 13 d ago also GHSA-jj45-xvq5-rhh9 , GO-2026-5471 , EUVD-2026-25669

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

A security flaw has been discovered in go-kratos kratos up to 2.9.2. This impacts the function NewServer of the file transport/http/server.go of the component http.DefaultServeMux Fallback Handler. The manipulation results in unintended intermediary. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks. The patch is identified as 0284a5bcf92b5a7ee015300ce3051baf7ae4718d. Applying a patch is advised to resolve this issue.

Patch / fix

  • govulncheck-vulndb SLES 16.0, SLES for SAP applications 16.0 0.0.20260727T201416-160000.1.1

suse advisories SUSE-SU-2026:23216-1SUSE-SU-2026:23227-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260727T201416-160000.1.1

opensuse advisories openSUSE-SU-2026:21551-1

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-2026-6993 updated cvss 5.3

go-kratos: go-kratos kratos: Information disclosure via unintended HTTP server intermediary

  • 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-rhel9
    +34 more products
    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 ExternalDNS Operator edo/external-dns-rhel8, edo/external-dns-rhel9 Red Hat Fence Agents Remediation Operator workload-availability/fence-agents-remediation-rhel8-operator 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 Machine Deletion Remediation Operator workload-availability/machine-deletion-remediation-rhel8-operator Red Hat Migration Toolkit for Applications 8 mta/mta-cli-rhel9 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-registry-rhel8 Red Hat Multiarch Tuning Operator multiarch-tuning/multiarch-tuning-rhel9-operator Red Hat Multicluster Engine for Kubernetes multicluster-engine/discovery-rhel9 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 Node HealthCheck Operator workload-availability/node-healthcheck-rhel8-operator, node-healthcheck-operator-tech-preview/node-healthcheck-operator-rhel8, node-healthcheck-operator-tech-preview/node-healthcheck-rhel8-operator Red Hat OpenShift API for Data Protection oadp/oadp-velero-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, ossm-2/openshift-golang-builder-container Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, ossm-2/openshift-golang-builder-container Red Hat OpenShift Source-to-Image (S2I) source-to-image/source-to-image-rhel8 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 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8 Red Hat AMQ Broker 7 amq7/amq-broker-rhel9-operator Red Hat Ansible Automation Platform 2 receptor, python3.11-galaxy-ng, python3.12-galaxy-ng, automation-gateway-proxy, automation-gateway-proxy-openssl30, automation-gateway-proxy-openssl32, +2 more Red Hat build of Apache Camel - HawtIO 4 rhbac-4/hawtio-rhel8-operator, rhbac-4/hawtio-rhel9-operator, rhbac-4-tech-preview/hawtio-rhel8-operator Red Hat build of Apicurio Registry 2 apicurio/apicurio-registry-rhel8-operator, apicurio/apicurio-registry-rhel9-operator Red Hat Ceph Storage 5 rhceph/snmp-notifier-rhel8
    affected: workaround, no fix available “Fix deferred”

37 more affected, 1 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
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/go-kratos/kratos/issues/3810 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C
CNA 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N/E:POC/RL:OF/RC:C
CNA 4.0 5.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/go-kratos/kratos/v2
<=2.9.2
all versions
 no fix listed

Affected products

  • go-kratos kratos

Classification

Weakness
  • CWE-441 Unintended Proxy or Intermediary

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.