CVE-2021-40116

HighCVSS 7.5/10Last modified Aug 11, 2026

Description

Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.The vulnerability is due to improper handling of the Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. An attacker could exploit this vulnerability by sending a crafted IP packet to the affected device. A successful exploit could allow the attacker to cause through traffic to be dropped. Note: Only products with Snort3 configured and either a rule with Block with Reset or Interactive Block with Reset actions configured are vulnerable. Products configured with Snort2 are not vulnerable.

Metrics

CVSS 3.1 7.5/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

CWE-241

Affected software

No affected versions have been published.

Timeline

Published
Oct 27, 2021
Last modified
Aug 11, 2026
NVD status
Modified

Related CVEs from 2021

CVE-2021-401177.5A vulnerability in SSL/TLS message handler for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) SofCVE-2021-401187.5A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) SCVE-2021-401199.8A vulnerability in the key-based SSH authentication mechanism of Cisco Policy Suite could allow an unauthenticated, remote attacker to log iCVE-2021-401207.2A vulnerability in the web-based management interface of certain Cisco Small Business RV Series Routers could allow an authenticated, remoteCVE-2021-401214.8Multiple vulnerabilities in the web-based management interface of Cisco Identity Services Engine (ISE) Software could allow an attacker to cCVE-2021-401227.5A vulnerability in an API of the Call Bridge feature of Cisco Meeting Server could allow an unauthenticated, remote attacker to cause a deniCVE-2021-401236.5A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an authenticated, remote attacker CVE-2021-401247.8A vulnerability in the Network Access Manager (NAM) module of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticatCVE-2021-401256.5A vulnerability in the Internet Key Exchange Version 2 (IKEv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco CVE-2021-401264.3A vulnerability in the web-based dashboard of Cisco Umbrella could allow an authenticated, remote attacker to perform an email enumeration aCVE-2021-401275.3A vulnerability in the web-based management interface of Cisco Small Business 200 Series Smart Switches, Cisco Small Business 300 Series ManCVE-2021-401285.3A vulnerability in the account activation feature of Cisco Webex Meetings could allow an unauthenticated, remote attacker to send an account
CVE-2021-40116: High severity, CVSS 7.5 | Vulnix