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                            CERT-Renater

                Note d'Information No. 2025/VULN748
_____________________________________________________________________

DATE                : 30/10/2025

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running ISC KEA versions prior to
                                 3.0.2, 3.1.3.

=====================================================================
https://kb.isc.org/docs/cve-2025-11232
_____________________________________________________________________

CVE-2025-11232: Invalid characters cause assert

    Published on Oct 29, 2025 

    Darren Ankney


CVE: CVE-2025-11232

Title: Invalid characters cause assert

Document version: 2.0

Posting date: 29 October 2025

Program impacted: Kea


Versions affected:

Kea

    3.0.1 -> 3.0.1
    3.1.1 -> 3.1.2


Versions NOT affected:

Kea

    2.6.0 -> 2.6.4
    2.7.0 -> 2.7.9
    3.0.0 -> 3.0.0
    3.1.0 -> 3.1.0

(Versions prior to 2.6.0 were not assessed.)


Severity: High

Exploitable: Remotely

Description:

To trigger the issue, three configuration parameters must have
specific settings: "hostname-char-set" must be left at the default
setting, which is "[^A-Za-z0-9.-]"; "hostname-char-replacement"
must be empty (the default); and "ddns-qualifying-suffix" must NOT
be empty (the default is empty). DDNS updates do not need to be
enabled for this issue to manifest. A client that sends certain
option content would then cause kea-dhcp4 to exit unexpectedly.


Impact:

A denial of service from the repeated attacks against the Kea server

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.


Workarounds:

Setting "hostname-char-replacement" to anything other than an
empty value (suggestion: "x") is an effective workaround to
this issue, regardless of other settings.


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:

    3.0.2
    3.1.3


Acknowledgments:

ISC would like to thank Siniša Uskoković and Ralf Steuer from Vienna
University of Economics and Business for bringing this vulnerability
to our attention.


Document revision history:

    1.0 Early Notification, 22 October 2025
    2.0 Public disclosure, 29 October 2025

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


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.

The Knowledgebase article https://kb.isc.org/docs/cve-2025-11232 is
the complete and official security advisory document.


Legal Disclaimer:

Internet Systems Consortium (ISC) is providing this notice on an
"AS IS" basis. No warranty or guarantee of any kind is expressed
in this notice and none should be implied. ISC expressly excludes
and disclaims any warranties regarding this notice or materials
referred to in this notice, including, without limitation, any
implied warranty of merchantability, fitness for a particular
purpose, absence of hidden defects, or of non-infringement. Your
use or reliance on this notice or materials referred to in this
notice is at your own risk. ISC may change this notice at any
time. A stand-alone copy or paraphrase of the text of this
document that omits the document URL is an uncontrolled copy.
Uncontrolled copies may lack important information, be out of
date, or contain factual errors.


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