PT-2021-13519 · Cisco · Cisco Nexus 9000 Series Fabric Switches

Published 2021-08-25 · Updated 2021-09-02 · CVE-2021-1523

Positive Technologies (AI Summary)

CVSS v3.1

8.6

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions: Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode (affected versions not specified)

Description: The issue is caused by mishandling of ingress TCP traffic to a specific port, allowing an unauthenticated, remote attacker to cause a queue wedge on a leaf switch. This could result in critical control plane traffic being dropped, leading to a denial of service (DoS) condition where the leaf switches are unavailable. An attacker could exploit this by sending a stream of TCP packets to a specific port on a Switched Virtual Interface (SVI) configured on the device, causing a specific packet queue to queue network buffers but never process them.

Recommendations: At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Missing Release of Resource after Effective Lifetime

Weakness Enumeration

CWE-772

Related Identifiers

CVE-2021-1523

Affected Products

Cisco Nexus 9000 Series Fabric Switches

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2021-1523 · Security Note
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n9kaci-queue-wedge-cLDDEfKF · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-1523 · Vendor Advisory