CVE-2021-40114 Multiple Cisco Products Snort Memory Leak Denial of Service Vulnerability
Unauthenticated remote attackers can cause a denial of service by sending crafted ICMP packets to Cisco Firepower devices, exhausting memory resources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-40114?
CVE-2021-40114 is a medium-severity denial of service vulnerability in Cisco Secure Firewall Management Center, published on 27 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Multiple Cisco products are affected by a vulnerability in the way the Snort detection engine processes ICMP traffic 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 memory resource management while the Snort detection engine is processing ICMP packets. An attacker could exploit this vulnerability by sending a series of ICMP packets through an affected device. A successful exploit could allow the attacker to exhaust resources on the affected device, causing the device to reload.
Which versions are affected by CVE-2021-40114?
It affects 4 products.
Products include Cisco Secure Firewall Management Center, Cisco Secure Firewall Threat Defense, Cisco Unified Threat Defense, Snort Snort.
How do I fix CVE-2021-40114?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-40114 being exploited?
There is no known exploitation of CVE-2021-40114 in the wild and no public exploit code.
Other vulnerabilities in Cisco Secure Firewall Management Center
- CVE-2026-20079 Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel
- CVE-2026-20131 Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data
- CVE-2026-20316 Cisco Secure Firewall Management Center Use of Hard-coded Password
- CVE-2025-20265 Cisco Secure Firewall Management Center Software Radius Remote Code Execution Vulnerability
- CVE-2024-20424 Command injection in Cisco Firepower Management Center
Sources
Also known as ALPINE-CVE-2021-40114, GHSA-5v43-2p8q-45m6, UBUNTU-CVE-2021-40114.