Security readout for executives and security teams
Plain-English summary
CVE-2020-3186 can let an unauthenticated remote attacker bypass configured management access-list restrictions on Cisco Firepower Threat Defense. The business risk is unintended access to the management interface policy boundary, not direct takeover based on the provided CVSS data. Treat exposed management interfaces as the priority.
Executive priority
Prioritize remediation for internet-reachable or broadly reachable FTD management interfaces. Internal-only deployments still matter, but urgency is lower unless management access controls are relied on as a primary boundary.
Technical view
The flaw is in Cisco FTD management access-list configuration handling. When different management ACLs allow ports in one list and deny them in another, crafted remote management traffic to the device local IP may bypass intended deny policy. CVSS 3.0 is 5.3 with network access, low complexity, no privileges, and low integrity impact.
Likely exposure
Exposure is most likely on Cisco Firepower Threat Defense deployments using management access lists with conflicting allow and deny behavior. The source bundle does not provide specific affected version ranges, so teams must verify against Cisco’s advisory and their installed FTD inventory.
Exploitation context
The CVE is not listed as CISA KEV in the provided bundle, and no cited source states active exploitation. Exploitation requires network reachability to the affected system’s local IP management path and a vulnerable ACL configuration pattern.
Researcher notes
Evidence supports an ACL policy bypass, not confidentiality loss or availability impact. The bundle does not name fixed versions, workaround specifics, proof-of-concept availability, or real-world exploitation. Keep analysis tied to Cisco advisory details when validating affected releases.
Mitigation direction
- Identify Cisco FTD appliances and compare software releases against Cisco’s advisory.
- Follow Cisco’s advisory for fixed releases or vendor-approved workaround guidance.
- Limit management interface reachability to trusted administration networks.
- Review management ACL design for conflicting allow and deny rules across lists.
Validation and detection
- Inventory all Cisco Firepower Threat Defense systems and their management interface exposure.
- Check whether management ACLs use overlapping allow and deny rules across different lists.
- Confirm installed FTD versions against Cisco’s advisory, since versions are not in the bundle.
- Review logs for unexpected management-interface traffic reaching denied services.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-3186 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.3MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20200506 Cisco Firepower Threat Defense Software Management Access List Bypass VulnerabilityCVE 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 Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.