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Fencer Vulns
high 7.5

CVE-2025-40779 json

Kea crash upon interaction between specific client options and subnet selection

published 2025-08-27 14 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-27981

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

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.

Patch / fix

  • ISC Kea 2.6.0
  • kea RHEL 10.1 3.0.1-1.el10_1
  • kea-libs RHEL 10.1 3.0.1-1.el10_1
  • kea-hooks RHEL 10.1 3.0.1-1.el10_1
  • kea-keama RHEL 10.1 3.0.1-1.el10_1

red hat advisories RHSA-2025:21006

  • kea openSUSE Leap 16.0 3.0.1-160000.1.1
  • kea openSUSE Tumbleweed 3.0.1-1.1

opensuse advisories openSUSE-SU-2026:20341-1openSUSE-SU-2025:15499-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-40779 updated cvss 7.5

kea: Kea crash upon interaction between specific client options and subnet selection

  • Red Hat Enterprise Linux AppStream (v. 10) kea-hooks 3.0.1-1.el10_1 Red Hat Enterprise Linux BaseOS (v. 10) kea 3.0.1-1.el10_1, kea-libs 3.0.1-1.el10_1 Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kea-keama 3.0.1-1.el10_1
    fixed: vendor fix RHSA-2025:21006

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
14 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • ISC Kea

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.