etcd is a distributed key-value store for the data of a distributed system

Overview

etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.5.33, 3.6.14, and 3.7.1, a network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. In client/pkg/transport/listener_tls.go, each connection handled by tlsListener.acceptLoop spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() and remains tracked in the pending map. Unbounded goroutine and map growth can exhaust memory in the etcd process, causing loss of availability for the cluster and, when etcd backs Kubernetes, the control plane. This issue is fixed in versions 3.5.33, 3.6.14, and 3.7.1.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Package advisory (CVE-2026-73500)

Affected packages:

• go.etcd.io/etcd/v3 >= 3.7.0-alpha.0, < 3.7.1
• go.etcd.io/etcd/v3 >= 3.6.0, < 3.6.14
• go.etcd.io/etcd/v3 < 3.5.33

Patched in:

• go.etcd.io/etcd/v3 3.7.1
• go.etcd.io/etcd/v3 3.6.14
• go.etcd.io/etcd/v3 3.5.33

Source: https://osv.dev/vulnerability/GHSA-6vch-q96h-7gc3

Vendor advisories

• RHSA-2026:44868 · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-24 · advisory
• Red Hat VEX · Important · affected: cert-manager Operator for Red Hat OpenShift, ExternalDNS Operator, Multicluster Engine for Kubernetes, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat Ceph Storage 5, Red Hat Ceph Storage 6, … · no fix planned: Multicluster Engine for Kubernetes, cert-manager Operator for Red Hat OpenShift, ExternalDNS Operator, Red Hat Advanced Cluster Management for Kubernetes 2, … · updated 2026-09-21 · vex
• RHSA-2026:67516 · Red Hat · fixed in: Multicluster Global Hub 1.4.9 · released 2026-09-15 · advisory