Secure Firewall Management CenterApplication · Cisco
CVE-2020-3557
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA vulnerability in the host input API daemon of Cisco Firepower Management Center allows an unauthenticated remote attacker to cause denial of service by sending a crafted data stream. The root cause is improper certificate validation, which allows the daemon to crash and restart, potentially continuously upon repeated attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Secure Firewall Management CenterApplication
< 6.6.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify the installed productConfirm Cisco Firepower Management Center (FMC) or Cisco Secure Firewall Management Center is deployed in your environment. Check system inventory, installed software, or the management console for the product name.Affected if The product is not Cisco Firepower Management Center or Secure Firewall Management Center
-
Check the FMC versionLog into the Firepower Management Center web interface and navigate to Help > About, or run 'show version' via CLI on the FMC device. Note the displayed version number.Affected if The installed version is lower than 6.6.1 (e.g., 6.5.0, 6.4.0, etc.)
-
Determine if host input API daemon is enabledAccess the FMC CLI and run 'show running-config | include host' or check the management interface settings. The host input API daemon (host_input service) listens on a specific port for external connections.Affected if The host input API daemon is enabled and listening for connections
-
Assess network exposure of the daemonReview firewall rules, access lists, and network segmentation surrounding the FMC management interface. Determine if the host input API port is reachable from untrusted networks or the internet.Affected if The management interface with host input API is exposed to untrusted or internet-facing networks
You are affected if your FMC version is below 6.6.1 AND the host input API daemon is enabled and reachable from untrusted networks.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data6.6.1
Apply the vendor-provided patch from Cisco when available. In the interim, consider network segmentation and access controls to limit exposure of the host input daemon to untrusted networks.
Fix this in Secure Firewall Management Center
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3557 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3557 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data