Security readout for executives and security teams
Plain-English summary
This is a denial-of-service risk for Cisco Firepower 4110 appliances running Cisco FTD Software. A remote unauthenticated attacker could trigger memory exhaustion and an unexpected device reload using crafted ICMP or ICMPv6 traffic. The main business impact is firewall/security appliance availability, not data theft.
Executive priority
Treat as high priority for affected Cisco Firepower 4110 deployments because the vulnerable device may be a security control or network choke point. Prioritize validation and vendor-guided remediation, especially for externally reachable appliances.
Technical view
Cisco describes incomplete input validation in ICMP ingress packet processing. The affected target is Cisco FTD Software on Firepower 4110 appliances. Successful exploitation can exhaust memory and reload the device; recovery after reload is automatic. CVSS is 8.6 high, with network attack vector and no privileges or user interaction required.
Likely exposure
Exposure is limited to environments using Cisco Firepower 4110 appliances with Cisco FTD Software. Risk is higher where ICMP or ICMPv6 traffic can reach the affected device from untrusted networks. The bundle does not provide affected version ranges.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation evidence. Exploitation is described as remote and unauthenticated, causing availability impact through crafted ICMP or ICMPv6 packet floods. No confidentiality or integrity impact is stated.
Researcher notes
Evidence is strong for vulnerability mechanics and impact, but incomplete for affected version ranges and specific fixes in the provided bundle. Do not claim active exploitation based on these sources. Focus validation on product presence, traffic reachability, software version mapping, and reload telemetry.
Mitigation direction
- Inventory Cisco Firepower 4110 appliances running Cisco FTD Software.
- Check Cisco’s advisory for affected releases, fixed software, and supported mitigations.
- Prioritize updates or mitigations for internet-facing or untrusted-network reachable appliances.
- Review perimeter controls for unnecessary ICMP and ICMPv6 reachability to affected devices.
- Ensure operational monitoring detects unexpected reloads and availability loss.
Validation and detection
- Confirm whether any Firepower 4110 appliances run Cisco FTD Software.
- Compare installed software versions against Cisco advisory guidance.
- Review logs and uptime history for unexpected reloads around ICMP traffic spikes.
- Verify exposure paths for ICMP and ICMPv6 to the device.
- Document whether compensating controls reduce untrusted traffic reachability.
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
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ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2020-3571 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
- High
- CVSS
- 8.6 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.6HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20201021 Cisco Firepower 4110 ICMP Flood Denial of Service 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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.