# 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.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Oct 2021
- **Updated:** 7 Nov 2024
- **Also known as:** ALPINE-CVE-2021-40114, GHSA-5v43-2p8q-45m6, UBUNTU-CVE-2021-40114

## 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.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime), CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2021-40114?

It affects 4 products.


Products: 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.

## 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](https://insights.sbomify.com/CVE-2026-20079/): Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel (critical 10.0, exploited in the wild)
- [CVE-2026-20131](https://insights.sbomify.com/CVE-2026-20131/): Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data (critical 10.0, exploited in the wild)
- [CVE-2026-20316](https://insights.sbomify.com/CVE-2026-20316/): Cisco Secure Firewall Management Center Use of Hard-coded Password (medium 5.3, exploited in the wild)
- [CVE-2025-20265](https://insights.sbomify.com/CVE-2025-20265/): Cisco Secure Firewall Management Center Software Radius Remote Code Execution Vulnerability (critical 10.0)
- [CVE-2024-20424](https://insights.sbomify.com/CVE-2024-20424/): Command injection in Cisco Firepower Management Center (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40114 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2021-40114 in the wild and no public exploit code.

Affected product: Cisco Secure Firewall Management Center. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-40114/ (Markdown: https://insights.sbomify.com/CVE-2021-40114/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40114
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40114
- OSV: https://osv.dev/vulnerability/CVE-2021-40114

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-40114/
Summaries are generated and may contain mistakes; the official description above is the record.