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CVE-2026-42944

Опубликовано: 20 мая 2026
Источник: redhat
CVSS3: 7.5

Описание

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.

A flaw was found in Unbound, a Domain Name System (DNS) resolver. A remote attacker could trigger a heap overflow by sending specially crafted DNS reply packets. This occurs when Unbound attempts to encode multiple Name Server Identifier (NSID) or Extension Mechanisms for DNS (EDNS) Cookie options, or EDNS Padding options, and these options are enabled. Successful exploitation of this vulnerability could lead to a denial of service (DoS), making the Unbound service unavailable.

Меры по смягчению последствий

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Enterprise Linux 6unboundWill not fix
Red Hat Enterprise Linux 7unboundAffected
Red Hat OpenShift Container Platform 4rhcosAffected
Red Hat Enterprise Linux 10unboundFixedRHSA-2026:2323104.06.2026
Red Hat Enterprise Linux 8unboundFixedRHSA-2026:2436508.06.2026
Red Hat Enterprise Linux 9unboundFixedRHSA-2026:2436908.06.2026
Red Hat Hardened Imagesunbound-main-1.25.1-0.1.hum1FixedRHSA-2026:1975220.05.2026

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Дополнительная информация

Статус:

Important
https://bugzilla.redhat.com/show_bug.cgi?id=2479774unbound: Heap overflow and crash with multiple nsid, cookie, padding EDNS options

7.5 High

CVSS3

Связанные уязвимости

CVSS3: 7.5
ubuntu
2 месяца назад

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.

CVSS3: 7.5
nvd
2 месяца назад

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.

CVSS3: 7.5
msrc
2 месяца назад

Heap overflow with multiple NSID, COOKIE, PADDING EDNS options

CVSS3: 7.5
debian
2 месяца назад

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vul ...

CVSS3: 7.5
redos
20 дней назад

Уязвимость unbound

7.5 High

CVSS3