Security readout for executives and security teams
Plain-English summary
This is a denial-of-service flaw in Cisco Firepower Threat Defense. If an affected device processes malicious GRE-over-IPv6 traffic, it can crash and interrupt firewall/security enforcement. The business impact is availability loss at a network control point, not data theft or code execution based on the provided sources.
Executive priority
Treat as high priority for networks that rely on Cisco FTD for perimeter, segmentation, or critical service protection. The main risk is outage at a security control point. Prioritize exposed GRE-over-IPv6 deployments first.
Technical view
CVE-2020-3179 affects Cisco FTD GRE tunnel decapsulation. A memory handling error, mapped to CWE-415, can be triggered remotely without authentication by crafted GRE-over-IPv6 packets carrying IPv4 or IPv6 payloads through an affected device, causing a crash. CVSS 3.0 is 8.6 with high availability impact.
Likely exposure
Exposure is most likely where Cisco FTD processes GRE-over-IPv6 tunnel traffic from untrusted or semi-trusted networks. The source bundle does not provide affected version ranges, so teams must verify against Cisco's advisory and their deployed FTD versions.
Exploitation context
The source bundle does not indicate active exploitation, and KEV status is false. Exploitation is network-reachable, low complexity, unauthenticated, and requires the vulnerable GRE-over-IPv6 processing path to be reachable through the affected device.
Researcher notes
The provided data confirms product, attack vector, impact, CVSS, CWE, and vendor advisory. It does not include exact affected versions, fixed versions, workarounds, or exploit-in-the-wild evidence. Avoid assuming broader Cisco product exposure.
Mitigation direction
- Review Cisco's advisory for affected and fixed FTD releases.
- Apply the vendor-recommended FTD software update through normal change control.
- Limit GRE-over-IPv6 exposure to trusted paths where operationally possible.
- Disable unused GRE-over-IPv6 tunnel handling if Cisco guidance supports it.
- Monitor affected devices for crash or reload events.
Validation and detection
- Inventory Cisco FTD devices and deployed software versions.
- Confirm whether GRE-over-IPv6 tunnel decapsulation is enabled or required.
- Check whether untrusted GRE-over-IPv6 traffic can reach affected devices.
- Review device logs for unexplained crashes, reloads, or DoS symptoms.
- Compare findings with Cisco's advisory before closing remediation.
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-415: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2020-3179 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
- 20200506 Cisco Firepower Threat Defense Software Generic Routing Encapsulation Tunnel IPv6 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.
Double Free
Double Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.