CVE-2021-1587

moderate-risk

Published 2021-08-25

A vulnerability in the VXLAN Operation, Administration, and Maintenance (OAM) feature of Cisco NX-OS Software, known as NGOAM, could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of specific packets with a Transparent Interconnection of Lots of Links (TRILL) OAM EtherType. An attacker could exploit this vulnerability by sending crafted packets, including the TRILL OAM EtherType of 0x8902, to a device that is part of a VXLAN Ethernet VPN (EVPN) fabric. A successful exploit could allow the attacker to cause an affected device to experience high CPU usage and consume excessive system resources, which may result in overall control plane instability and cause the affected device to reload. Note: The NGOAM feature is disabled by default.

Do I need to act?

0.57% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 8.6/10 High

NETWORK / LOW complexity

Affected Products (1)

Nx-Os

Affected Vendors

Cisco

References (2)

Patch https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n...

/ 100

moderate-risk

Severity 29/34 · Critical

Exploitability 2/34 · Minimal

Exposure 5/34 · Minimal