---
id: CVE-2023-20185
title: >-
  Cisco ACI Multi-Site CloudSec Encryption Information Disclosure Vulnerability
  (CVE-2023-20185)
summary: "A vulnerability in the Cisco ACI Multi-Site CloudSec encryption feature of Cisco Nexus 9000 Series Fabric Switches in ACI mode could allow an unauthenticated, remote attacker to read or modify intersite encrypted traffic.\r\n\r\nThis vulnerabi…"
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cvssSource: vendor
vendor: Cisco
product: Cisco Nexus 9000 Series Switches
affected:
  - nexus_9000_series_switches
published: '2023-07-05'
updated: '2026-04-24'
sourceUpdated: '2026-04-24T13:05:36+00:00'
source: CSAF
sourceUrl: >-
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-aci-cloudsec-enc-Vs5Wn2sX
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-aci-cloudsec-enc-Vs5Wn2sX
  - url: 'https://software.cisco.com'
tags:
  - csaf
  - vendor-advisory
  - cisco
epss: 0.00343
epssPercentile: 0.25788
ingestedAt: '2026-10-10T08:18:41.023Z'
---

## Overview

A vulnerability in the Cisco ACI Multi-Site CloudSec encryption feature of Cisco Nexus 9000 Series Fabric Switches in ACI mode could allow an unauthenticated, remote attacker to read or modify intersite encrypted traffic.

This vulnerability is due to an issue with the implementation of the ciphers that are used by the CloudSec encryption feature on affected switches. An attacker with an on-path position between the ACI sites could exploit this vulnerability by intercepting intersite encrypted traffic and using cryptanalytic techniques to break the encryption. A successful exploit could allow the attacker to read or modify the traffic that is transmitted between the sites.

Cisco has deprecated and removed the ACI Multi-Site CloudSec encryption feature that is affected by this vulnerability. There are no workarounds that address this vulnerability.

## Vendor advisories

- **cisco-sa-aci-cloudsec-enc-Vs5Wn2sX** · Cisco · affected: Cisco Nexus 9000 Series Switches · updated 2026-04-24 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-aci-cloudsec-enc-Vs5Wn2sX)

**Cisco ACI Multi-Site CloudSec Encryption Information Disclosure Vulnerability**. Released 2023-07-05, updated 2026-04-24.

Affected:

- Cisco Nexus 9000 Series Switches

## Remediation

Cisco has released software updates that address this vulnerability. https://software.cisco.com