etcd: `tlsListener.acceptLoop` spawns unbounded handshake goroutines with no deadline

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-73500
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-12 22:17:17 UTC
Updated2026-08-13 18:18:17 UTC
Descriptionetcd 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.

Risk And Classification

Primary CVSS: v4.0 8.7 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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

Problem Types: CWE-770 | CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Etcd-io Etcd affected < 3.5.33 Not specified
CNA Etcd-io Etcd affected >= 3.6.0, < 3.6.14 Not specified
CNA Etcd-io Etcd affected >= 3.7.0-alpha.0, < 3.7.1 Not specified

References

ReferenceSourceLinkTags
github.com/etcd-io/etcd/commit/2e07efce9745004eb4773cffaada9b5cdf77cff2 [email protected] github.com
github.com/etcd-io/etcd/security/advisories/GHSA-6vch-q96h-7gc3 [email protected] github.com
github.com/etcd-io/etcd/commit/f73cba7d920019f91a1ea1f6697833e42731f057 [email protected] github.com
github.com/etcd-io/etcd/releases/tag/v3.6.14 [email protected] github.com
github.com/etcd-io/etcd/pull/22130 [email protected] github.com
github.com/etcd-io/etcd/commit/89ff6d50796049d4f1136915ba21504b76e7e372 [email protected] github.com
github.com/etcd-io/etcd/releases/tag/v3.7.1 [email protected] github.com
github.com/etcd-io/etcd/releases/tag/v3.5.33 [email protected] github.com
github.com/etcd-io/etcd/commit/8e4dd0679a2c6b095d2a32a749fda2521c7809a3 [email protected] github.com
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