What is CVE-2026-4437?

CVE-2026-4437 is a high-severity vulnerability in Gnu Glibc, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-03-20.

How severe is CVE-2026-4437?

High severity. CVSS v3 base score is 7.5 out of 10.

Out-of-bounds Read in Gnu Glibc

CVE-2026-4437

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.

Vulnerability class: Buffer Overflow

EPSS: 0.003 (24.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Gnu Glibc
The Gnu C Library Glibc — versions 2.34

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

3ff69d7a-14f2-4f67-a097-88dee7810d18 (Exploit, Patch, Issue Tracking)
0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

Frequently asked questions

What is CVE-2026-4437?: CVE-2026-4437 is a high-severity vulnerability in Gnu Glibc, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-03-20.
How severe is CVE-2026-4437?: High severity. CVSS v3 base score is 7.5 out of 10.