CVE-2026-4437

Name: CVE-2026-4437
Creator: NVD / NIST
Published: 2026-03-20T20:16:49.477+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.29%

Last modified Jun 17, 2026

CVE-2026-4437 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.29%

20.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

Affected Software

Vendor	Product	Versions
Gnu	Glibc	>= 2.34, <= 2.43

References

https://sourceware.org/bugzilla/show_bug.cgi?id=34014Exploit, Issue Tracking, Patch

Timeline

Published: Mar 20, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-4437?

How severe is CVE-2026-4437?

CVE-2026-4437 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4437?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-4437?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST