CVE-2026-73500: CWE-770: Allocation of Resources Without Limits or Throttling in etcd-io etcd
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.
AI Analysis
Technical Summary
The vulnerability arises from the handling of incoming TLS connections in etcd's tlsListener.acceptLoop, where each new connection spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() if the client never sends a ClientHello message. These goroutines accumulate in the pending map without limits, leading to uncontrolled resource consumption. This can result in memory exhaustion and denial of service of the etcd process, impacting cluster availability. Fixed versions are 3.5.33, 3.6.14, and 3.7.1.
Potential Impact
An unauthenticated remote attacker can cause a denial of service by exhausting memory resources on the etcd server through many incomplete TLS connections. This can disrupt the availability of the etcd cluster and any systems relying on it, such as Kubernetes control planes, potentially causing widespread service disruption.
Mitigation Recommendations
A fix is available in etcd versions 3.5.33, 3.6.14, and 3.7.1. Users should upgrade to one of these versions or later to remediate this vulnerability. No other mitigation or temporary workaround is indicated in the provided data.
CVE-2026-73500: CWE-770: Allocation of Resources Without Limits or Throttling in etcd-io etcd
Description
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.
CVSS v4.0
Score 8.7high
Affected software
etcd-io
etcd
pkg:golang/github.com/etcd-io/etcdRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability arises from the handling of incoming TLS connections in etcd's tlsListener.acceptLoop, where each new connection spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() if the client never sends a ClientHello message. These goroutines accumulate in the pending map without limits, leading to uncontrolled resource consumption. This can result in memory exhaustion and denial of service of the etcd process, impacting cluster availability. Fixed versions are 3.5.33, 3.6.14, and 3.7.1.
Potential Impact
An unauthenticated remote attacker can cause a denial of service by exhausting memory resources on the etcd server through many incomplete TLS connections. This can disrupt the availability of the etcd cluster and any systems relying on it, such as Kubernetes control planes, potentially causing widespread service disruption.
Mitigation Recommendations
A fix is available in etcd versions 3.5.33, 3.6.14, and 3.7.1. Users should upgrade to one of these versions or later to remediate this vulnerability. No other mitigation or temporary workaround is indicated in the provided data.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-12T19:00:33.736Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a7ce89cbf8831d5393450ef
Added to database: 08/12/2026, 21:41:48 UTC
Last enriched: 08/12/2026, 21:56:11 UTC
Last updated: 09/26/2026, 01:47:44 UTC
Views: 74
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