CVE-2026-73500

CVE-2026-73500 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

• Severity: High (CVSS 4.0 base score 8.7)
• EPSS exploit prediction: 0% (33rd percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-770
• Published: 2026-08-12
• Last modified: 2026-08-13

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.

Frequently asked questions

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.

How severe is CVE-2026-73500?

CVE-2026-73500 has a CVSS 4.0 base score of 8.7, rated high severity.

Is CVE-2026-73500 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-73500?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-73500 published?

CVE-2026-73500 was published on 2026-08-12 and last updated on 2026-08-13.

References

• https://github.com/etcd-io/etcd/commit/2e07efce9745004eb4773cffaada9b5cdf77cff2
• https://github.com/etcd-io/etcd/commit/89ff6d50796049d4f1136915ba21504b76e7e372
• https://github.com/etcd-io/etcd/commit/8e4dd0679a2c6b095d2a32a749fda2521c7809a3
• https://github.com/etcd-io/etcd/commit/f73cba7d920019f91a1ea1f6697833e42731f057
• https://github.com/etcd-io/etcd/pull/22130
• https://github.com/etcd-io/etcd/releases/tag/v3.5.33
• https://github.com/etcd-io/etcd/releases/tag/v3.6.14
• https://github.com/etcd-io/etcd/releases/tag/v3.7.1
• https://github.com/etcd-io/etcd/security/advisories/GHSA-6vch-q96h-7gc3

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