CVE-2025-40779
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-08-27

Last updated on: 2025-11-04

Assigner: Internet Systems Consortium (ISC)

Description
If a DHCPv4 client sends a request with some specific options, and Kea fails to find an appropriate subnet for the client, the `kea-dhcp4` process will abort with an assertion failure. This happens only if the client request is unicast directly to Kea; broadcast messages do not cause the problem. This issue affects Kea versions 2.7.1 through 2.7.9, 3.0.0, and 3.1.0.
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Meta Information
Published
2025-08-27
Last Modified
2025-11-04
Generated
2026-06-16
AI Q&A
2025-08-27
EPSS Evaluated
2026-06-14
NVD
CVE-2025-40779
Affected Vendors & Products
Showing 11 associated CPEs
Vendor Product Version / Range
isc kea 3.0.0
isc kea 2.7.9
isc kea 2.7.3
isc kea 2.7.1
isc kea 2.7.5
isc kea 2.7.2
isc kea 2.7.4
isc kea 3.1.0
isc kea 2.7.7
isc kea 2.7.6
isc kea 2.7.8
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
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Executive Summary

This vulnerability occurs in the Kea DHCP server versions 2.7.1 through 2.7.9, 3.0.0, and 3.1.0. When a DHCPv4 client sends a request with certain specific options and Kea cannot find an appropriate subnet for that client, the kea-dhcp4 process crashes due to an assertion failure. This crash happens only if the client request is sent via unicast directly to the Kea server; broadcast requests do not cause this issue. The crash results in the DHCP service stopping, causing a denial of service. [1]

Impact Analysis

The impact of this vulnerability is a denial of service (DoS) condition on the DHCPv4 service. A single malicious or misconfigured DHCP client sending a crafted unicast request can cause the kea-dhcp4 process to abort, disrupting DHCP service availability. This can prevent clients from obtaining IP addresses, potentially causing network outages or connectivity issues. [1]

Mitigation Strategies

To mitigate this vulnerability, you should upgrade your Kea DHCP server to the patched versions 3.0.1 or 3.1.1, depending on your current version. There are no known workarounds, so applying the update is the recommended immediate step to prevent the kea-dhcp4 process from aborting and causing a denial of service. [1]

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