CVE-2026-4437
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | Low | N/A | None |
| Availability Impact | Low | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
Frequently Asked Questions
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