Cisco is letting customers know about a serious security flaw that has been discovered in some Nexus switches. This bug, monitored as CVE-2020-10136, has been given an 8.6 / 10 on the severity score.

This vulnerability allows traffic from the attacker’s machine to directly infiltrate the target’s network by circumventing Access Control Lists. If used repeatedly, the bug can actually cause the device’s network stack to crash which results in a denial of service.

Impacted products include those on the following list:

• Nexus 1000 Virtual Edge for VMware vSphere
• Nexus 1000V Switch for Microsoft Hyper-V
• Nexus 1000V Switch for VMware vSphere
• Nexus 3000 Series Switches
• Nexus 5500 Platform Switches
• Nexus 5600 Platform Switches
• Nexus 6000 Series Switches
• Nexus 7000 Series Switches
• Nexus 9000 Series Switches in standalone NX-OS mode
• UCS 6200 Series Fabric Interconnects
• UCS 6300 Series Fabric Interconnects

Our recommendation is to execute the Cisco update as soon as possible.