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Vulnerability record · CVE-2026-4437 · published 20 March 2026

CVE-2026-4437: Gnu glibc out-of-bounds read vulnerability

Gnu · Glibc

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.

7.5 CVSS 3.1 High EPSS 0.49% · top 60.1% CWE-125 · Out-of-bounds read
7.5CVSS 3.1 base score
0.49%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 1 tagged exploit
14 Jul 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://sourceware.org/bugzilla/show_bug.cgi?id=34014 ExploitIssue TrackingPatch
https://cert-portal.siemens.com/productcert/html/ssa-082556.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-4437), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.