CVE-2026-4437

A flaw was found in glibc (the GNU C Library). When an application uses the gethostbyaddr or gethostbyaddr_r functions with a nsswitch.conf configuration that specifies glibc's DNS backend, a remote attacker can send a specially crafted DNS (Domain Name System) response. This crafted response can cause the application to incorrectly interpret a non-answer section of the DNS response as a valid answer, leading to potential misbehavior or incorrect information processing.

This MODERATE impact flaw in glibc allows a remote attacker to send a specially crafted DNS response when an application uses gethostbyaddr or gethostbyaddr_r with glibc's DNS backend configured in nsswitch.conf. This can lead to incorrect interpretation of DNS responses. Red Hat Enterprise Linux versions 6, 7, 8, 9, and 10, as well as OpenShift Container Platform, are affected if applications are configured to use the vulnerable DNS backend.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.