Denial of Service Vulnerability in Cisco Nexus 3000 and 9000 Series Switches

CVE-2025-20111

What is CVE-2025-20111?

CVE-2025-20111 is a denial of service (DoS) vulnerability present in Cisco's Nexus 3000 and 9000 Series Switches when they operate in standalone NX-OS mode. These switches are crucial components in many organizations' network infrastructures, providing advanced switching capabilities for data centers and enterprise networks. The vulnerability allows an unauthenticated adjacent attacker to disrupt the operation of the device by sending specially crafted Ethernet frames, potentially leading to unexpected device reloads. If exploited, this vulnerability can severely impact an organization's network availability and reliability.

Technical Details

The vulnerability arises from improper handling of specific Ethernet frames, which allows an attacker to initiate a reload of the affected switches. This can be executed by sending a consistent stream of maliciously crafted Ethernet frames to the device. The device's health monitoring diagnostics fail to appropriately manage this specific scenario, resulting in a denial of service condition. This issue highlights vulnerabilities in network infrastructure components that can be detrimental to overall network performance.

Potential impact of CVE-2025-20111

1. Network Downtime: The primary impact of CVE-2025-20111 is the potential for significant network downtime. An attacker exploiting this vulnerability can cause switches to reload unexpectedly, disrupting network services and affecting all devices connected through the impacted switches.

2. Reduced Productivity: As network availability is compromised, organizations can experience a decline in productivity. Critical applications that rely on continuous network access may become unavailable, leading to frustration and delays in business operations.

3. Resource Allocation for Incident Response: Organizations affected by this vulnerability may need to allocate additional resources for incident response and recovery efforts. This includes monitoring for potential attacks, troubleshooting downed systems, and implementing measures to prevent future occurrences, diverting attention and resources away from other important initiatives.

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