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Firepower Management Center Virtual ApplianceApplication · Cisco

CVE-2021-34756

HIGH · 7.8 CVSS v3.1 Published 2021-10-27
Fix available
A fix is available. Upgrade to 6.4.0.13 / 6.6.5 or later.
See remediation →
80/100
Remediation priority · High
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
Multiple vulnerabilities in the CLI of Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary commands with root privileges. For more information about these vulnerabilities, see the Details section of this advisory.

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

Multiple vulnerabilities in the CLI of Cisco Firepower Threat Defense (FTD) allow an authenticated local attacker to execute arbitrary commands with root privileges. This is a local privilege escalation issue where the attacker needs valid local credentials but can then escape restricted shell contexts to run commands as root.

MitigationApply the relevant Cisco FTD software update/ patch from Cisco to remediate these CLI vulnerabilities. Prioritize patching given the high CVSS score and local privilege escalation impact.

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 Management Center Virtual ApplianceApplication
Affected:= 6.1.0= 6.2.0= 6.2.3= 6.3.0= 6.4.0= 6.4.0.11= 6.5.0= 6.6.0= 6.6.1= 6.7.0= 7.0.0= 7.1.0
Secure Firewall Threat DefenseApplication
Affected:>= 6.4.0, < 6.4.0.13>= 6.6.0, < 6.6.5>= 6.7.0, < 6.7.0.3>= 7.0.0, < 7.0.1
Sourcefire Defense CenterApplication
Affected:= 6.1.0= 6.2.0= 6.2.3= 6.3.0= 6.4.0= 6.4.0.11= 6.5.0= 6.6.0= 6.6.1= 6.7.0= 7.0.0= 7.1.0

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 checks

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

  1. Identify the installed product
    Log into the CLI and run 'show version' or check the system prompt to determine if the device is Firepower Management Center (FMC) Virtual Appliance, Firepower Threat Defense (FTD), or Sourcefire Defense Center
    Affected if The device is not one of these three product types, the vulnerability does not apply
  2. Determine the FTD software version
    Run the command 'show version' in the FTD CLI and locate the displayed software version number
    Affected if The version shown is 6.4.0 through 6.4.0.12, 6.6.0 through 6.6.4, 6.7.0 through 6.7.0.2, or 7.0.0
  3. Determine the FMC Virtual Appliance version
    Run the command 'show version' in the FMC CLI and locate the displayed software version number
    Affected if The version shown matches exactly one of these: 6.1.0, 6.2.0, 6.2.3, 6.3.0, 6.4.0, 6.4.0.11, 6.5.0, 6.6.0, 6.6.1, 6.7.0, 7.0.0, or 7.1.0
  4. Determine the Sourcefire Defense Center version
    Run the command 'show version' in the Defense Center CLI and locate the displayed software version number
    Affected if The version shown matches exactly one of these: 6.1.0, 6.2.0, 6.2.3, 6.3.0, 6.4.0, 6.4.0.11, 6.5.0, 6.6.0, 6.6.1, 6.7.0, 7.0.0, or 7.1.0

The device is affected if it is any of the three products (FMC Virtual Appliance, FTD, or Sourcefire Defense Center) AND its installed version falls within the specific ranges or exact versions listed in the affected products list.

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 6.4.0.13 / 6.6.5 / 6.7.0.3 or later
Fixed in 6.4.0.136.6.56.7.0.3
Interim mitigation

Apply the relevant Cisco FTD software update/ patch from Cisco to remediate these CLI vulnerabilities. Prioritize patching given the high CVSS score and local privilege escalation impact.

Recommended fix High confidence

Upgrade to 6.4.0.13+ (for 6.4.x), 6.6.5+ (for 6.6.x), 6.7.0.3+ (for 6.7.x), or 7.0.1+ (for 7.0.x). For FMC/SFDC 6.1-6.3, upgrade to the next stable release beyond 6.3.0.

  1. 1. Identify the currently installed FTD or FMC version by running 'show version' in the CLI
  2. 2. Based on the current version line, upgrade to the first fixed release: For 6.4.x - upgrade to 6.4.0.13 or later; For 6.6.x - upgrade to 6.6.5 or later; For 6.7.x - upgrade to 6.7.0.3 or later; For 7.0.x - upgrade to 7.0.1 or later; For 6.1.x-6.3.x (FMC/SFDC) - upgrade to a version beyond 6.3.0 following Cisco's release chain
  3. 3. Download the appropriate upgrade package from Cisco (requires valid Smart License)
  4. 4. Upload the upgrade package to the device via 'system install' CLI command or FMC web interface
  5. 5. Reboot the device after installation completes
  6. 6. Verify the version upgrade was successful with 'show version'
  7. 7. Since this is a local command injection vulnerability, also review user access and limit local CLI access to only necessary admin accounts
Caveat Verify compatibility with your deployment and ensure Smart Licensing is active before upgrading. Major version jumps may require careful planning and testing.

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

Fix this in Firepower Management Center Virtual Appliance Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2021-34756 in production — separate from our analysis above.

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