Security readout for executives and security teams
Plain-English summary
This is a critical Cisco Nexus 9000 ACI Mode switch flaw involving a shared default SSH key. If an attacker can reach SSH over IPv6 and has the key material, they could log in as root. IPv4 is not affected according to the source bundle.
Executive priority
Treat this as urgent for network infrastructure teams if Nexus 9000 ACI fabric switches are present. Root access to fabric switches can affect confidentiality, integrity, and availability of critical network services. Prioritize inventory, IPv6 SSH exposure review, and Cisco-guided remediation.
Technical view
CVE-2019-1804 affects Cisco Nexus 9000 Series Fabric Switches in ACI Mode due to default SSH key material present across devices. Exploitation is unauthenticated, remote, IPv6-only, low complexity, and can provide root privileges. The listed affected software is Cisco NX-OS for Nexus 9000 ACI Mode 11.0.1b.
Likely exposure
Exposure is most likely where Cisco Nexus 9000 fabric switches run ACI Mode affected software and accept SSH over IPv6. Environments without IPv6 SSH reachability are less exposed to this specific path. IPv4 is explicitly not vulnerable in the provided source.
Exploitation context
The source describes a remote unauthenticated path requiring IPv6 SSH reachability and extracted key material. CISA KEV status is false in the bundle, and no provided source states active exploitation. The impact is severe because successful access is root-level.
Researcher notes
The key constraints are Cisco Nexus 9000 ACI Mode, default SSH key management, and IPv6-only exploitability. The bundle does not provide exploit availability, patch details, or active exploitation evidence. Validation should focus on affected asset identification, IPv6 SSH reachability, and vendor version guidance.
Mitigation direction
- Identify Cisco Nexus 9000 fabric switches running ACI Mode affected software.
- Review the Cisco advisory for fixed releases and vendor-supported remediation.
- Apply Cisco-recommended software updates or mitigations where applicable.
- Restrict IPv6 SSH management access to trusted administration networks.
- Monitor for unauthorized root-level access and unexpected SSH sessions.
Validation and detection
- Confirm device model and ACI operating mode against the Cisco advisory.
- Check whether SSH is reachable over IPv6 from untrusted networks.
- Verify installed software version against Cisco’s affected and fixed version guidance.
- Review authentication and system logs for unexpected IPv6 SSH activity.
- Document whether IPv4-only management assumptions are masking IPv6 exposure.
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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CWE-310: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-1804 mapping review
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Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
9.8CriticalVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190501 Cisco Nexus 9000 Series Fabric Switches Application Centric Infrastructure Mode Default SSH Key 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.
Cryptographic Issues
Cryptographic Issues represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.