CVE-2026-4437

CVE-2026-4437: gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

Vendor The Gnu C Library

Product glibc

Weakness CWE-125

Published March 20, 2026

Last update March 23, 2026

View on NVD All CVEs

CVSS base score

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What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 20, 2026 CVE published

March 23, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-4437 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/125.html