CVE-2026-50045
Description
A vulnerability in Unbound allows a remote attacker to bypass upstream amplification limits by querying a deeply nested name under a DNSSEC-signed parent. This triggers excessive outbound traffic per query, potentially causing a denial of service (DoS).
Statement
A Moderate flaw in Unbound allows remote attackers to bypass max-global-quota limits using crafted DNSSEC queries. This causes upstream traffic amplification, potentially leading to a Denial of Service (DoS). This issue specifically affects Unbound versions 1.22.0 through 1.25.1.
Mitigation
Restrict recursive DNS access strictly to trusted networks using firewall access controls, reloading the service to apply changes. Additionally, configure Rate Limiting on outbound traffic to throttle anomalous spikes and mitigate amplification risks.
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 | 5.3 | N/A | 5.3 |
| 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 | None | N/A | None |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Amplification; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
System resources can be quickly consumed leading to poor application performance or system crash. This may affect network performance and could be used to attack other systems and applications relying on network performance.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
