---
id: CVE-2024-20373
title: Cisco IOS and Cisco IOS XE SNMP Extended ACL Bypass Vulnerability
summary: >-
  A vulnerability in the implementation of the Simple Network Management
  Protocol (SNMP) IPv4 access control list (ACL) feature of Cisco IOS Software
  and Cisco IOS XE Software could allow an unauthenticated, remote attacker to
  perform SNMP p…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'
cvssSource: vendor
vendor: Cisco
product: IOS
affected:
  - 1000_series_integrated_services_routers
  - asr_1000_series_aggregation_services_routers
  - ios_xe_software 3.9.0E
  - ios_xe_software 3.8.2E
  - ios_xe_software 3.8.3E
  - ios_xe_software 3.9.1E
  - ios_xe_software 3.8.4E
  - ios_xe_software 3.9.2E
  - ios_xe_software 3.8.5E
  - ios_xe_software 3.10.0E
  - ios_xe_software 3.9.2bE
  - ios_xe_software 16.11.1
  - ios_xe_software 16.12.1
  - ios_xe_software 3.10.1E
  - ios_xe_software 3.8.5aE
  - ios_xe_software 3.10.0cE
  - ios_xe_software 3.8.6E
  - ios_xe_software 3.10.2E
  - ios_xe_software 3.10.1aE
  - ios_xe_software 3.8.7E
  - ios_xe_software 3.10.1sE
  - ios_xe_software 3.11.0E
  - ios_xe_software 17.1.1
  - ios_xe_software 3.8.8E
  - ios_xe_software 16.9.3
  - ios_xe_software 17.2.1
  - ios_xe_software 16.11.1a
  - ios_xe_software 16.6.6
  - ios_xe_software 17.3.1
  - ios_xe_software 16.9.3h
  - ios_xe_software 16.11.1b
  - ios_xe_software 16.11.2
  - ios_xe_software 16.6.7
  - ios_xe_software 16.11.1s
  - ios_xe_software 16.9.4
  - ios_xe_software 16.9.3s
  - ios_xe_software 17.4.1
  - ios_xe_software 17.5.1
  - ios_xe_software 17.6.1
  - ios_xe_software 3.10.3E
published: '2024-04-17'
updated: '2024-04-17'
sourceUpdated: '2024-04-17T16:00:00+00:00'
source: CSAF
sourceUrl: >-
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-uwBXfqww
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-uwBXfqww
  - url: 'https://software.cisco.com'
tags:
  - csaf
  - vendor-advisory
  - cisco
epss: 0.005
epssPercentile: 0.40416
ingestedAt: '2026-09-27T07:45:38.476Z'
---

## Overview

A vulnerability in the implementation of the Simple Network Management Protocol (SNMP) IPv4 access control list (ACL) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to perform SNMP polling of an affected device, even if it is configured to deny SNMP traffic.

This vulnerability exists because Cisco IOS Software and Cisco IOS XE Software do not support extended IPv4 ACLs for SNMP, but they do allow administrators to configure extended named IPv4 ACLs that are attached to the SNMP server configuration without a warning message. This can result in no ACL being applied to the SNMP listening process. An attacker could exploit this vulnerability by performing SNMP polling of an affected device. A successful exploit could allow the attacker to perform SNMP operations that should be denied. The attacker has no control of the SNMP ACL configuration and would still need a valid SNMP version 2c (SNMPv2c) community string or SNMP version 3 (SNMPv3) user credentials.

SNMP with IPv6 ACL configurations is not affected.

For more information, see the Details ["#details"] section of this advisory.

Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

## Vendor advisories

- **cisco-sa-snmp-uwBXfqww** · Cisco · affected: Cisco 1000 Series Integrated Services Routers, Cisco ASR 1000 Series Aggregation Services Routers, Cisco IOS XE Software (166 versions), IOS (221 versions) · updated 2024-04-17 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-uwBXfqww)

**Cisco IOS and IOS XE Software SNMP Extended Named Access Control List Bypass Vulnerability**. Released 2024-04-17.

Affected:

- Cisco 1000 Series Integrated Services Routers
- Cisco ASR 1000 Series Aggregation Services Routers
- Cisco IOS XE Software 3.9.0E
- Cisco IOS XE Software 3.8.2E
- Cisco IOS XE Software 3.8.3E
- Cisco IOS XE Software 3.9.1E
- Cisco IOS XE Software 3.8.4E
- Cisco IOS XE Software 3.9.2E
- Cisco IOS XE Software 3.8.5E
- Cisco IOS XE Software 3.10.0E
- Cisco IOS XE Software 3.9.2bE
- Cisco IOS XE Software 16.11.1
- Cisco IOS XE Software 16.12.1
- Cisco IOS XE Software 3.10.1E
- Cisco IOS XE Software 3.8.5aE
- Cisco IOS XE Software 3.10.0cE
- Cisco IOS XE Software 3.8.6E
- Cisco IOS XE Software 3.10.2E
- Cisco IOS XE Software 3.10.1aE
- Cisco IOS XE Software 3.8.7E
- Cisco IOS XE Software 3.10.1sE
- Cisco IOS XE Software 3.11.0E
- Cisco IOS XE Software 17.1.1
- Cisco IOS XE Software 3.8.8E
- Cisco IOS XE Software 16.9.3
- Cisco IOS XE Software 17.2.1
- Cisco IOS XE Software 16.11.1a
- Cisco IOS XE Software 16.6.6
- Cisco IOS XE Software 17.3.1
- Cisco IOS XE Software 16.9.3h
- Cisco IOS XE Software 16.11.1b
- Cisco IOS XE Software 16.11.2
- Cisco IOS XE Software 16.6.7
- Cisco IOS XE Software 16.11.1s
- Cisco IOS XE Software 16.9.4
- Cisco IOS XE Software 16.9.3s
- Cisco IOS XE Software 17.4.1
- Cisco IOS XE Software 17.5.1
- Cisco IOS XE Software 17.6.1
- Cisco IOS XE Software 3.10.3E

## Remediation

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