# CVE-2026-73500 — etcd-io etcd

> As of 2026-08-12, CVE-2026-73500 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in etcd-io etcd, CVSS v4.0 8.7. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-73500 as of 2026-08-12; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-12

## What is CVE-2026-73500?

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.

The record classifies CVE-2026-73500 under weakness class [CWE-770](https://intel.threadlinqs.com/cwe/CWE-770). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 54 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.7 — High (derived from score) (`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`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-12

## Is CVE-2026-73500 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **etcd-io**: etcd

## How to fix CVE-2026-73500

No vendor patch reference has been recorded for CVE-2026-73500 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-73500

No threat campaign in the Threadlinqs corpus currently references CVE-2026-73500, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD. Last verified by Threadlinqs on 2026-08-14. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/etcd-io/etcd/security/advisories/GHSA-6vch-q96h-7gc3)

**Other references**

- [github.com](https://github.com/etcd-io/etcd/pull/22130)
- [github.com (2e07efce9745004eb4773cffaada9b5cdf77cff2)](https://github.com/etcd-io/etcd/commit/2e07efce9745004eb4773cffaada9b5cdf77cff2)
- [github.com (89ff6d50796049d4f1136915ba21504b76e7e372)](https://github.com/etcd-io/etcd/commit/89ff6d50796049d4f1136915ba21504b76e7e372)
- [github.com (8e4dd0679a2c6b095d2a32a749fda2521c7809a3)](https://github.com/etcd-io/etcd/commit/8e4dd0679a2c6b095d2a32a749fda2521c7809a3)
- [github.com (f73cba7d920019f91a1ea1f6697833e42731f057)](https://github.com/etcd-io/etcd/commit/f73cba7d920019f91a1ea1f6697833e42731f057)

_Showing 6 of 9 recorded references._

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-73500
Full detection coverage and IOCs for threats exploiting CVE-2026-73500 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp