Detections
Analytics
Cisco Nexus 3600 9500-R Series Switching Platforms Layer 2 Loop DoS (cisco-sa-nxos-ether-dos-Kv8YNWZ4)
high Nessus Plugin ID 301245
Synopsis
The remote device is missing a vendor-supplied security patchDescription
According to its self-reported version, Cisco NX-OS Software is affected by a vulnerability.- A vulnerability with the Ethernet VPN (EVPN) Layer 2 ingress packet processing of Cisco Nexus 3600 Platform Switches and Cisco Nexus 9500-R Series Switching Platforms could allow an unauthenticated, adjacent attacker to trigger a Layer 2 traffic loop. This vulnerability is due to a logic error when processing a crafted Layer 2 ingress frame. An attacker could exploit this vulnerability by sending a stream of crafted Ethernet frames through the targeted device. A successful exploit could allow the attacker to cause a Layer 2 Virtual eXtensible LAN (VxLAN) traffic loop, which, in turn, could result in a denial of service (DoS) condition. This Layer 2 loop could oversubscribe the bandwidth on network interfaces, which would result in all data plane traffic being dropped. To exploit this vulnerability, the attacker must be Layer 2-adjacent to the affected device. Note:To stop active exploitation of this vulnerability, manual intervention is required to both stop the crafted traffic and flap all involved network interfaces. For additional assistance if a Layer 2 loop that is related to this vulnerability is suspected, contact the Cisco Technical Assistance Center (TAC) or the proper support provider.
(CVE-2026-20051)
Please see the included Cisco BIDs and Cisco Security Advisory for more information.
Solution
Upgrade to the relevant fixed version referenced in Cisco bug ID CSCwo94451See Also
http://www.nessus.org/u?561b5269
Plugin Details
Severity: High
ID: 301245
File Name: cisco-sa-nxos-ether-dos-Kv8YNWZ4.nasl
Version: 1.1
Type: combined
Family: CISCO
Published: 3/6/2026
Updated: 3/6/2026
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 5.2
CVSS v2
Risk Factor: Medium
Base Score: 6.1
Temporal Score: 4.5
Vector: CVSS2#AV:A/AC:L/Au:N/C:N/I:N/A:C
CVSS Score Source: CVE-2026-20051
CVSS v3
Risk Factor: High
Base Score: 7.4
Temporal Score: 6.4
Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: cpe:/o:cisco:nx-os
Required KB Items: Host/Cisco/NX-OS/Version, Host/Cisco/NX-OS/Model, Host/Cisco/NX-OS/Device
Exploit Ease: No known exploits are available
Patch Publication Date: 2/25/2026
Vulnerability Publication Date: 2/25/2026
Reference Information
CVE: CVE-2026-20051