Security readout for executives and security teams
Plain-English summary
Cisco Firepower Threat Defense has CLI command injection vulnerabilities that could let a logged-in local attacker run commands as root. The business risk is serious if untrusted or compromised administrators can access the appliance CLI, but the source indicates high privileges and local access are required.
Executive priority
Treat this as a prioritized administrative-plane risk, not a broad remote emergency. Remediate affected FTD systems after confirming vendor guidance, especially where privileged access controls are weak or the device protects critical environments.
Technical view
CVE-2021-34756 covers multiple CWE-20 command injection issues in Cisco FTD Software CLI. CVSS 3.1 is 6.7 with AV:L/AC:L/PR:H/UI:N/S:U and high confidentiality, integrity, and availability impact. The bundle does not identify affected versions beyond the product name.
Likely exposure
Exposure is most likely in organizations running Cisco Firepower Threat Defense Software where local CLI access is available to administrators or tightly privileged accounts. The provided data does not list specific vulnerable versions.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. Exploitation requires an authenticated local attacker with high privileges, which reduces broad internet exposure but increases concern for compromised admin accounts or insider risk.
Researcher notes
Key evidence gaps remain in the provided bundle: affected version ranges, fixed versions, and detailed conditions are not included. Analysis should stay anchored to Cisco’s advisory before making fleet-specific exposure or remediation claims.
Mitigation direction
- Review Cisco’s advisory for affected releases and fixed software guidance.
- Restrict FTD CLI access to trusted administrative users only.
- Audit privileged accounts with access to FTD appliances.
- Monitor administrative CLI activity for unexpected command execution patterns.
- Prioritize remediation where FTD protects sensitive or critical network segments.
Validation and detection
- Inventory Cisco Firepower Threat Defense appliances and software versions.
- Compare deployed versions against the Cisco advisory’s affected and fixed release details.
- Confirm CLI access is limited to authorized administrators.
- Review recent privileged CLI activity for suspicious behavior.
- Check whether FTD management access is exposed beyond trusted networks.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-20: Exact CWE lookup
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Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-34756 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20211027 Cisco Firepower Threat Defense Software Command Injection VulnerabilitiesCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.