CVE-2021-40116

HIGH

Cisco Firepower Threat Defense 6.4.0-6.4.0.12 & Snort 3.0.0.0-3.0.99.99 - DoS via Snort Rule Block

Title source: llm
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 8.6
EPSS 0.0078
EPSS Percentile 73.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-241
Status published
Products (3)
cisco/firepower_threat_defense 6.4.0 - 6.4.0.13
cisco/secure_firewall_management_center 3.1.0.1
cisco/snort 3.0.0.0 - 3.1.0.100
Published Oct 27, 2021
Tracked Since Feb 18, 2026