Firepower Extensible Operating SystemOperating system · Cisco
CVE-2020-3545
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 Cisco FXOS Software could allow an authenticated, local attacker with administrative credentials to cause a buffer overflow condition. The vulnerability is due to incorrect bounds checking of values that are parsed from a specific file. An attacker could exploit this vulnerability by supplying a crafted file that, when it is processed, may cause a stack-based buffer overflow. A successful exploit could allow the attacker to execute arbitrary code on the underlying operating system with root privileges. An attacker would need to have valid administrative credentials to exploit this vulnerability.
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 stack-based buffer overflow vulnerability in Cisco FXOS Software stems from insufficient bounds checking when parsing values from a specific file. An authenticated attacker with administrative credentials can exploit this by supplying a specially crafted file, potentially executing arbitrary code with root privileges on the underlying operating system.
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
Firepower Extensible Operating SystemOperating system
<= 2.3.1.58CVSS 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
- Local
- Complexity
- Low
- Privileges
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
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.
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Identify FXOS versionLog into the FXOS CLI and run the command 'show version' or 'show system software' to display the installed Cisco FXOS software versionAffected if The displayed version number is 2.3.1.58 or lower (any version <= 2.3.1.58)
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Confirm administrative access existsReview user accounts configured on the FXOS system using 'show user-account' or check authentication settings to determine if administrative-level accounts are presentAffected if Administrative ( privilege level 15) user accounts exist on the system, as the vulnerability requires authenticated attacker with admin credentials
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Verify file import functionality is accessibleCheck if the FXOS system allows file imports or configuration uploads via the CLI ('import configuration'), API, or web interface. Review accessible file parsing features in the system.Affected if File import or configuration upload features are accessible to authenticated administrative users, as the vulnerability is triggered when parsing a specially crafted file
A system is affected if it runs Cisco FXOS version 2.3.1.58 or lower AND has administrative user accounts with access to file import/parsing functionality.
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 dataApply the Cisco vendor patch for CVE-2020-3545 when available. Until patched, strictly control administrative access and monitor for suspicious file imports to the FXOS system.
Fix this in Firepower Extensible Operating System
Scoped from the published advisory
- Consultation6.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,144.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3545 — 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-2020-3545 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
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- 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
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