Cisco Secure Firewall Management Center
CVE-2021-40116
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.
What this means for your business
- It affects Cisco Secure Firewall Management Center. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 1% chance of attack attempts being seen in the next 30 days, ranking above 70% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Cisco Secure Firewall Management Center, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 8.6 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- Weakness
- CWE-241
- Assigned by
- psirt@cisco.com
Dates
- Published
- 2021-10-27
- Last modified
- 2026-08-11
- Sources
- NVD
Affected products
- Cisco Secure Firewall Management Center3.1.0.1
- Cisco Secure Firewall Threat Defense6.4.0 - 6.4.0.13, 6.6.0 - 6.6.5.1, 6.7.0 - 6.7.0.3, 7.0.0 - 7.0.1
- Cisco Snort3.0.0.0 - 3.1.0.100
As listed in the NVD configuration data. Not a statement about your estate.