# CVE-2020-3557: Cisco Firepower Management Center Software Denial of Service Vulnerability

> Unauthenticated remote attackers can cause a denial of service on Cisco Firepower Management Center by exploiting improper certificate validation in the host input API daemon.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Oct 2020
- **Updated:** 13 Nov 2024
- **Also known as:** GHSA-4g3g-c4gj-wqr7

## What is CVE-2020-3557?

CVE-2020-3557 is a medium-severity denial of service vulnerability in Cisco Secure Firewall Management Center, published on 21 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the host input API daemon of Cisco Firepower Management Center (FMC) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper certificate validation. An attacker could exploit this vulnerability by sending a crafted data stream to the host input daemon of the affected device. A successful exploit could allow the attacker to cause the host input daemon to restart. The attacker could use repeated attacks to cause the daemon to continuously reload, creating a DoS condition for the API.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2020-3557?

It affects 1 product.


Products: Cisco Secure Firewall Management Center.

## How do I fix CVE-2020-3557?

No fix has been published for CVE-2020-3557 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3557 being exploited?

There is no known exploitation of CVE-2020-3557 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-2020-3557 and fix it if it is affected.

What it is: CVE-2020-3557 is a medium-severity denial of service vulnerability in Cisco Secure Firewall Management Center, published on 21 Oct 2020. 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-2020-3557 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-2020-3557/ (Markdown: https://insights.sbomify.com/CVE-2020-3557/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3557
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3557
- OSV: https://osv.dev/vulnerability/CVE-2020-3557

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3557/
Summaries are generated and may contain mistakes; the official description above is the record.