CVE-2026-73500

Ein Angreifer kann mehrere Schwachstellen in etcd ausnutzen, um Sicherheitsvorkehrungen zu umgehen, und um einen Denial of Service Angriff durchzuführen.

### Impact _What kind of vulnerability is it? Who is impacted?_ A network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. Each connection spawns a goroutine in the etcd server process that blocks indefinitely inside tls.Conn.Handshake(), and each is tracked in the pending map. Unbounded goroutine and map growth exhausts memory in the etcd process, causing loss of availability for the etcd cluster (and, when etcd backs Kubernetes, the control plane). ### Patches _Has the problem been patched? What versions should users upgrade to?_ This vulnerability is patched in the following versions: - etcd 3.7.1 - etcd 3.6.14 - etcd 3.5.33 ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ If upgrading is not immediately possible, then restrict network access. Limit which hosts can reach etcd's client (gRPC) port via firewall rules or network policy, reducing who can attempt exploitation. ### Reporter VMware By Broadcom

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.

In go.etcd.io/etcd/client/pkg/v3 before 3.5.33, 3.6.14, and 3.7.1, TLS handshakes on listeners created by NewTLSListener do not enforce a handshake deadline. An unauthenticated network attacker who connects to an etcd TLS listener without sending a ClientHello causes a goroutine and a tracking map entry to block indefinitely. Opening many such connections exhausts memory, leading to a denial of service.