CVE-2026-4438

Name: CVE-2026-4438
Creator: NVD / NIST
Published: 2026-03-20T20:16:49.623+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 0.19%

Last modified Jun 17, 2026

CVE-2026-4438 is a medium-severity vulnerability rated 5.4/10 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 result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.. EPSS estimates a 0.19% 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 result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.

Metrics

CVSS 3.1

5.4/10

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

EPSS Probability

0.19%

8.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

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

References

https://sourceware.org/bugzilla/show_bug.cgi?id=34015Exploit, Issue Tracking, Patch

Timeline

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

Frequently Asked Questions

What is CVE-2026-4438?

How severe is CVE-2026-4438?

CVE-2026-4438 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4438?

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-2026-4438?

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

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Source: NVD / NIST