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wid-sec-w-2026-0817  ·  Published 2026-03-22  ·  View on BSI CERT-Bund ↗

GNU libc: Multiple Vulnerabilities allow Manipulation from DNS Antworten

CVSS 7.5 HIGH

Risk Summary

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. 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.

Affected Vendors

Open Source

Affected Products (1)

Open Source · GNU libc 2.34-2.43

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