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Firepower Management Center Virtual ApplianceApplication · Cisco

CVE-2021-34762

HIGH · 8.1 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 →
87/100
Remediation priority · High
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 web-based management interface of Cisco Firepower Management Center (FMC) Software could allow an authenticated, remote attacker to perform a directory traversal attack on an affected device. The attacker would require valid device credentials. The vulnerability is due to insufficient input validation of the HTTPS URL by the web-based management interface. An attacker could exploit this vulnerability by sending a crafted HTTPS request that contains directory traversal character sequences to an affected device. A successful exploit could allow the attacker to read or write arbitrary files on the 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 directory traversal vulnerability in Cisco Firepower Management Center's web-based management interface allows authenticated attackers to read or write arbitrary files by sending crafted HTTPS requests with directory traversal character sequences (e.g., ../../). The vulnerability stems from insufficient input validation of the HTTPS URL by the interface.

MitigationApply the vendor patch from Cisco when available, and limit access to the FMC web management interface to trusted administrators only until the patch is applied.

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:= 6.2.3= 6.4.0= 6.5.0= 6.6.1= 6.6.2= 6.6.3= 6.6.4= 6.7.0= 7.0.0= 7.1.0
Secure Firewall Threat DefenseApplication
Affected:< 6.4.0.13>= 6.5.0, < 6.6.5>= 6.7.0, < 6.7.0.3>= 7.0.0, < 7.0.1
Sourcefire Defense CenterApplication
Affected:= 6.2.3= 6.4.0= 6.5.0= 6.6.1= 6.6.2= 6.6.3= 6.6.4= 7.0.0

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

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

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 Cisco product
    Log into the device CLI or check the system overview in the web interface to confirm the product name (Firepower Management Center Virtual Appliance, Sourcefire Defense Center, or Firepower Threat Defense)
    Affected if The product is not one of the three listed (FMC Virtual Appliance, Sourcefire Defense Center, or Firepower Threat Defense)
  2. Determine the software version
    Run the command 'show version' in the CLI, or check the Dashboard > System > Summary in the web interface to locate the installed version number
    Affected if The version matches or falls within the affected ranges: FMC Virtual Appliance or Sourcefire Defense Center versions 6.2.3, 6.4.0, 6.5.0, 6.6.1-6.6.4, 7.0.0, 7.1.0; or FTD versions < 6.4.0.13, >= 6.5.0 and < 6.6.5, >= 7.0.0 and < 7.0.1, or >= 6.7.0 and < 6.7.0.3
  3. Verify the web-based management interface is accessible
    Confirm that the HTTPS management interface (typically port 443) is enabled and reachable on the device. Check via 'show interface' or review the management access configuration in the CLI
    Affected if The HTTPS web management interface is enabled and exposed (this is the attack surface for the vulnerability)
  4. Confirm authentication method
    Review whether local or remote administrator accounts are configured for the web interface by checking 'show admin-user' or reviewing the authentication settings in the web UI under System > Users > Users
    Affected if The web management interface has any authenticated user accounts configured (authentication is required for exploitation)

The environment is affected if it runs an affected Firepower product (FMC Virtual Appliance, Sourcefire Defense Center, or Firepower Threat Defense) with a version matching the affected ranges AND has the HTTPS web management interface enabled and accessible to authenticated administrators.

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 vendor patch from Cisco when available, and limit access to the FMC web management interface to trusted administrators only until the patch is applied.

Recommended fix High confidence

FMC: 6.7.0+ | FTD: 6.4.0.13, 6.6.5, 7.0.1, or 7.0.3+ depending on current branch

  1. 1. Identify the currently installed Cisco Firepower Management Center (FMC) or Firepower Threat Defense (FTD) version using 'show version' command
  2. 2. Determine which product line and version bracket your device falls into from the affected versions list
  3. 3. For Firepower Management Center Virtual Appliance or Sourcefire Defense Center: Upgrade to version 6.7.0 or later
  4. 4. For Firepower Threat Defense: If running < 6.4.0, upgrade to 6.4.0.13 or later; if running 6.5.0-6.6.4, upgrade to 6.6.5 or later; if running 6.7.0-6.7.0.2, upgrade to 7.0.3 or later; if running 7.0.0-7.0.0, upgrade to 7.0.1 or later
  5. 5. Download the appropriate firmware from Cisco's Software Download page (software.cisco.com) using valid Cisco credentials
  6. 6. Follow Cisco's standard upgrade procedure for FMC or FTD platforms, typically via the web UI or CLI
  7. 7. After upgrade, verify the new version is installed with 'show version' and confirm the vulnerability is remediated
Caveat Major version upgrades (e.g., 6.x to 7.x) may require compatibility checks with other Cisco security products and could involve configuration migration; test in staging before production deployment

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
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2021-34762 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data