CVE-2026-4437Suited to automated attack · CISA

gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

CVSS score

7.5

EPSS probability

%0.3

Risk score

0.0

Published

7 mo ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-4437 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-4437 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	The GNU C Library	glibc	View
2	gnu	glibc	View

Total affected vendors: 2|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
7.5	CVSS V31	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD
7.5	CVSS V3_1	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CVE ADP
5.9	CVSS 3.x	—	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	Microsoft MSRC

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source

reference

Yama veya çözüm referansı

Open source

Confirm the affected product and version against the source evidence above.

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Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-4437 is associated with the following CWEs:

CWE-125: Out-of-bounds Read

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-4437 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

https://sourceware.org/bugzilla/show_bug.cgi?id=34014vendor-advisory https://cert-portal.siemens.com/productcert/html/ssa-082556.htmlnvd https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgradepatch

CVSS Vector Radar Chart

7.5 / 10

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)High

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

The GNU C Library

gnu

Weakness Type (CWE & CAPEC)

CWE-125

Similar Vulnerabilities

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5.1

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7.8

CVE-2023-4911 Actively exploitedGlibc: buffer overflow in ld.so leading to privilege escalation

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7.3

CVE-2024-2961Out-of-bounds write in The GNU C Library Glibc

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Patch status unknownEPSS %882 y ago

7.4

CVE-2020-13777Vulnerability in N/a

Vendorn/a Productn/a+8 etkilenen

Patch status unknownEPSS %226 y ago

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