CVE-2025-40779Network attack vector

Remote DHCPv4 service crash via unicast request

Published Aug 27, 2025 · Updated Nov 4, 2025

Denial of service in ISC Kea DHCP 2.7.1 through 2.7.9, 3.0.0, and 3.1.0 allows remote attackers to crash kea-dhcp4 via one packet. The daemon reaches an assertion failure when a unicast DHCPv4 request carries specific options and subnet selection finds no appropriate subnet. Direct unicast reachability to the DHCPv4 service is required; broadcast requests do not trigger the crash, which interrupts DHCPv4 service.

CVSS severity7.5
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in ISC Kea DHCP 2.7.1 through 2.7.9, 3.0.0, and 3.1.0 allows remote attackers to crash kea-dhcp4 via one packet. The daemon reaches an assertion failure when a unicast DHCPv4 request carries specific options and subnet selection finds no appropriate subnet. Direct unicast reachability to the DHCPv4 service is required; broadcast requests do not trigger the crash, which interrupts DHCPv4 service.

The record

CVE
CVE-2025-40779
Published
Aug 27, 2025
Updated
Nov 4, 2025
Vendor
Internet Systems Consortium
Product
Kea DHCP
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.7.1 <=2.7.9
  2. Affected versionversion=3.0.0
  3. Affected versionversion=3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Internet Systems Consortium · Kea DHCPversion=2.7.1 <=2.7.9; version=3.0.0; version=3.1.0

Published CVSS scores

7.5Internet Systems ConsortiumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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