ISC Kea up to 2.7.9/3.0.0/3.1.0 DHCPv4 null pointer dereference

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic was found in ISC Kea up to 2.7.9/3.0.0/3.1.0. This affects an unknown part of the component DHCPv4 Handler. Executing a manipulation can lead to null pointer dereference. The identification of this vulnerability is CVE-2025-40779. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in ISC Kea up to 2.7.9/3.0.0/3.1.0 and classified as problematic. This vulnerability affects an unknown function of the component DHCPv4 Handler. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at kb.isc.org. This vulnerability was named CVE-2025-40779 since 04/16/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 258123 (FreeBSD : ISC KEA -- kea-dhcp4 aborts if client sends a broadcast request with particular options (f727fe60-8389-11f0-8438-001b217e4ee5)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.0.1 or 3.1.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (258123). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• ISC

Name

• Kea

Version

• 2.7.0
• 2.7.1
• 2.7.2
• 2.7.3
• 2.7.4
• 2.7.5
• 2.7.6
• 2.7.7
• 2.7.8
• 2.7.9
• 3.0
• 3.1.0

License

• open-source

Website

• Vendor: https://www.isc.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (isc): 🔒

CVSSv2info

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💳	💳	💳	💳	💳	💳
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 258123
Nessus Name: FreeBSD : ISC KEA -- kea-dhcp4 aborts if client sends a broadcast request with particular options (f727fe60-8389-11f0-8438-001b217e4ee5)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kea 3.0.1/3.1.1

Timelineinfo

04/16/2025 CVE reserved
08/28/2025 +134 days Advisory disclosed
08/28/2025 +0 days VulDB entry created
08/30/2025 +2 days VulDB entry last update

Sourcesinfo

Vendor: isc.org

Advisory: kb.isc.org
Status: Confirmed

CVE: CVE-2025-40779 (🔒)
GCVE (CVE): GCVE-0-2025-40779
GCVE (VulDB): GCVE-100-321664

Entryinfo

Created: 08/28/2025 07:40
Updated: 08/30/2025 05:55
Changes: 08/28/2025 07:40 (64), 08/30/2025 02:03 (2), 08/30/2025 05:55 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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