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CVE-2026-42959

Опубликовано: 20 мая 2026
Источник: ubuntu
Приоритет: medium
EPSS Низкий
CVSS3: 7.5

Описание

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.

РелизСтатусПримечание
devel

not-affected

1.25.1-1ubuntu1
esm-infra-legacy/trusty

released

1.4.22-1ubuntu4.14.04.3+esm3
esm-infra-legacy/xenial

released

1.5.8-1ubuntu1.1+esm3
esm-infra/bionic

released

1.6.7-1ubuntu2.6+esm4
esm-infra/focal

released

1.9.4-2ubuntu1.11+esm1
esm-infra/xenial

ignored

end of ESM support, was needs-triage
jammy

released

1.13.1-1ubuntu5.15
noble

released

1.19.2-1ubuntu3.8
questing

released

1.22.0-2ubuntu2.3
resolute

released

1.24.2-1ubuntu2.1

Показывать по

EPSS

Процентиль: 51%
0.00779
Низкий

7.5 High

CVSS3

Связанные уязвимости

CVSS3: 7.5
redhat
2 месяца назад

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.

CVSS3: 7.5
nvd
2 месяца назад

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.

CVSS3: 7.5
msrc
2 месяца назад

Crash during DNSSEC validation of malicious content

CVSS3: 7.5
debian
2 месяца назад

NLnet Labs Unbound up to and including version 1.25.0 has a denial of ...

CVSS3: 7.5
redos
20 дней назад

Уязвимость unbound

EPSS

Процентиль: 51%
0.00779
Низкий

7.5 High

CVSS3