---
title: "CVE-2026-3608: Stack overflow in Kea daemons"
slug: "cve-2026-3608"
description: "Sending a maliciously crafted message to Kea daemons over any configured API socket or HA listener can cause a stack overflow error."
updated: 2026-03-25T08:14:07Z
published: 2026-03-25T08:14:07Z
canonical: "kb.isc.org/cve-2026-3608"
---

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# CVE-2026-3608: Stack overflow in Kea daemons

**CVE:** [CVE-2026-3608](https://www.cve.org/CVERecord?id=CVE-2026-3608)

**Title:** Stack overflow in Kea daemons

**Document version:** 2.0

**Posting date:** 25 March 2026

**Program impacted:** [Kea](https://www.isc.org/kea/)

**Versions affected:**

Kea

- 2.6.0 -> 2.6.4
- 3.0.0 -> 3.0.2

**Severity:** High

**Exploitable:** Remotely

**Description:**

Sending a maliciously crafted message to the kea-ctrl-agent, kea-dhcp-ddns, kea-dhcp4, or kea-dhcp6 daemons over any configured API socket or HA listener can cause the receiving daemon to exit with a stack overflow error.

**Impact:**

Loss of DHCP services

**CVSS Score:** 7.5

**CVSS Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit: [https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H&version=3.1](https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H&version=3.1).

**Workarounds:**

Securing the API sockets with TLS, and requiring the client to authenticate with a certificate (mutual authentication), prevents the attacker from establishing an API connection to Kea. Set cert-required to true (the default) to require a client certificate. See: https://kea.readthedocs.io/en/stable/arm/security.html#tls-https-configuration

**Active exploits:**

We are not aware of any active exploits.

**Solution:**

Upgrade to the patched release most closely related to your current version of Kea:

- 2.6.5
- 3.0.3

**Acknowledgments:**

ISC would like to thank Ali Norouzi of Keysight for bringing this vulnerability to our attention.

**Document revision history:**

- 1.0 Early Notification, 18 March 2026
- 1.1 Added workaround, 20 March 2026
- 2.0 Public disclosure, 25 March 2026

**Do you still have questions?** Questions regarding this advisory should be mailed to [kea-security@isc.org](mailto:kea-security@isc.org) or posted as confidential GitLab issues at [https://gitlab.isc.org/isc-projects/kea/-/issues/new?issue[confidential]=true](https://gitlab.isc.org/isc-projects/kea/-/issues/new?issue%5Bconfidential%5D=true).

**Note:**

ISC patches only currently supported versions. When possible we indicate EOL versions affected. For current information on which versions are actively supported, please see [https://www.isc.org/download/](https://www.isc.org/download/).

**ISC Security Vulnerability Disclosure Policy:**

Details of our current security advisory policy and practice can be found in the ISC Software Defect and Security Vulnerability Disclosure Policy at [https://kb.isc.org/docs/aa-00861](https://kb.isc.org/docs/aa-00861).

The Knowledgebase article [https://kb.isc.org/docs/cve-2026-3608](https://kb.isc.org/docs/cve-2026-3608) is the complete and official security advisory document.

**Legal Disclaimer:**

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