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Fencer Intel
critical 9.1

CVE-2026-118264 json

Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls

published 17d ago modified 4d ago also EUVD-2026-112396 , GHSA-cxf3-9h37-7rr8 , GO-2026-6839

cvss
9.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

Echo is a Go web framework. From 4.0.0 until 4.16.1 and 5.4.1, Echo's Proxy middleware selects a raw tunnel from a client WebSocket upgrade request before verifying that the configured upstream accepted the upgrade. If the upstream rejects the upgrade with an ordinary keep-alive response, later HTTP requests on the connection are sent directly to that upstream without passing through Echo's router or route-specific middleware. This can bypass authentication or authorization enforced only by Echo routes, but requires an accessible proxy route, a cooperating rejected-upgrade response, and a target without independent upstream authorization. This issue is fixed in 4.16.1 and 5.4.1.

Patch / fix

  • go github.com/labstack/echo/v4 4.16.1
  • go github.com/labstack/echo/v5 5.4.1
  • labstack echo 4.16.1, 5.4.1

Is CVE-2026-118264 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-2026-118264 updated cvss 7.4

github.com/labstack/echo: Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls

  • Red Hat Ansible Automation Orchestrator 2026 ansible-automation-platform/automation-orchestrator-temporal-rhel9 Red Hat Cost Management On Premise costmanagement/costmanagement-ros-ocp-backend-rhel9 Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-grafana-rhel9 Red Hat Multicluster Global Hub 5 multicluster-globalhub/multicluster-globalhub-grafana-rhel9 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/acm-grafana-rhel9, rhacm2/acm-multicluster-observability-addon-rhel9
    affected: workaround, no fix available
  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 8 grafana, grafana-loki, grafana-mssql, grafana-mysql, grafana-selinux, grafana-graphite, +12 more Red Hat Enterprise Linux 9 grafana, grafana-selinux, osbuild-composer, osbuild-composer-core, osbuild-composer-worker, osbuild-composer-dnf-json Red Hat Enterprise Linux 10 grafana, osbuild-composer Red Hat OpenShift Virtualization 4 container-native-virtualization/hyperconverged-cluster-webhook-rhel9, container-native-virtualization/hyperconverged-cluster-operator-rhel9 Red Hat OpenShift Virtualization 5 container-native-virtualization/hyperconverged-cluster-operator-rhel9
    affected: workaround, no fix available

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
total
Assessed
10d ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 9.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 9.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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

Affected packages

ecosystem package affected fixed in
go github.com/labstack/echo/v4
>=4.0.0, <4.16.1
4.16.1
go github.com/labstack/echo/v5
>=5.0.0, <5.4.1
5.4.1

Affected products

  • labstack echo

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests
  • CWE-863 Incorrect Authorization

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.