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Firepower 9300 FirmwareOperating system · Cisco

CVE-2023-20200

MEDIUM · 6.3 CVSS v3.1 Published 2023-08-23
Fix available
A fix is available. Upgrade to 4.1 / 4.2 or later.
See remediation →
69/100
Remediation priority · Elevated
Remotely reachable Zero-click

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 · unedited
A vulnerability in the Simple Network Management Protocol (SNMP) service of Cisco FXOS Software for Firepower 4100 Series and Firepower 9300 Security Appliances and of Cisco UCS 6300 Series Fabric Interconnects could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the improper handling of specific SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: This vulnerability affects all supported SNMP versions. To exploit this vulnerability through SNMPv2c or earlier, an attacker must know the SNMP community string that is configured on an affected device. To exploit this vulnerability through SNMPv3, the attacker must have valid credentials for an SNMP user who is configured on the affected device.

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 · high confidence

A vulnerability in the SNMP service of Cisco FXOS Software for Firepower 4100/9300 Series and UCS 6300 Series Fabric Interconnects allows an authenticated attacker to send crafted SNMP requests that cause improper handling, leading to device reload and denial of service. Exploitation requires either knowledge of SNMPv2c community strings or valid SNMPv3 user credentials.

MitigationApply Cisco's patch when available. Until then, restrict SNMP access via ACLs, change community strings to non-default values, and prefer SNMPv3 with strong authentication and encryption to limit exposure.

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 9300 FirmwareOperating system
Affected:all versions
Firepower 4143 FirmwareOperating system
Affected:all versions
Firepower 4112 FirmwareOperating system
Affected:all versions
Ucs 6324 Fabric Interconnect FirmwareOperating system
Affected:>= 4.1, < 4.1\(3l\)>= 4.2, < 4.2\(3d\)
Firepower 4125 FirmwareOperating system
Affected:all versions
Firepower 4115Operating system
Affected:all versions
Ucs 6332 Fabric Interconnect FirmwareOperating system
Affected:>= 4.1, < 4.1\(3l\)>= 4.2, <= 4.2\(3b\)
Ucs 6332 16up Fabric Interconnect FirmwareOperating system
Affected:>= 4.1, < 4.1\(3l\)>= 4.2, < 4.2\(3b\)

CVSS 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
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify device model
    Run 'show version' or check device inventory to confirm the model is Firepower 4100/9300 series or UCS 6300 series Fabric Interconnect (6324, 6332, 6332 16up)
    Affected if Device model is Firepower 9300, 4143, 4112, 4125, 4115, or UCS 6324, 6332, 6332 16up
  2. Check firmware version
    Run 'show version' to identify the firmware version and compare against affected ranges. For Firepower models, all versions are affected. For UCS models, check if version is 4.1.x before 4.1(3l), 4.2.x before 4.2(3d), or 4.2.x at or below 4.2(3b)
    Affected if Firmware version falls within affected ranges or is any version for Firepower models
  3. Verify SNMP service is enabled
    Run 'show snmp' or examine running configuration with 'show run | include snmp' to determine if SNMP is configured and enabled
    Affected if SNMP is enabled and configured on the device
  4. Check SNMP configuration details
    Run 'show snmp community' for SNMPv2c community strings and 'show snmp user' for SNMPv3 user credentials to see what authentication is configured
    Affected if SNMPv2c with community strings (especially default ones) or SNMPv3 with user credentials is configured

Device is affected if it is a Firepower 4100/9300 or UCS 6300 series with SNMP enabled and a firmware version within the affected ranges, and the attacker has SNMP community strings or user credentials.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 4.1 / 4.2 or later
Fixed in 4.14.2
Interim mitigation

Apply Cisco's patch when available. Until then, restrict SNMP access via ACLs, change community strings to non-default values, and prefer SNMPv3 with strong authentication and encryption to limit exposure.

Recommended fix Moderate confidence

UCS 6300: Upgrade to FXOS 4.1(3l) or later, or 4.2(3d) or later. Firepower 4100/9300: Upgrade to Cisco FXOS version containing the CVE-2023-20200 fix (consult Cisco FXOS advisory).

  1. 1. Identify the exact model and current firmware version of the affected Cisco device using 'show version' or via Cisco FMC/FP4100/9300 web interface.
  2. 2. For Firepower 4100 series (4112, 4115, 4125, 4143, 9300): Check Cisco FXOS firmware compatibility and upgrade to a version that includes the SNMP fix. Consult Cisco FXOS release notes for the specific fixed release.
  3. 3. For UCS 6300 Series Fabric Interconnects (6324, 6332, 6332 16up): Upgrade firmware to version 4.1(3l) or later for the 4.1 branch, or 4.2(3d) or later for the 4.2 branch.
  4. 4. After upgrading firmware, verify SNMP service functionality and confirm the device remains stable after processing SNMP requests.
  5. 5. If immediate upgrade is not possible, consider disabling SNMP if not required, or restricting SNMP access to trusted management networks via ACLs.
Caveat Review Cisco FXOS upgrade requirements and ensure compatibility with upstream security manager (FMC). Upgrades may require downtime and configuration backup.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Firepower 9300 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation10.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,440
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-20200 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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