Security readout for executives and security teams
Plain-English summary
CVE-2019-1967 is a denial-of-service flaw in Cisco NX-OS NTP handling. A remote unauthenticated attacker could drive high CPU and memory use, causing process restarts or unexpected device reloads. Because NX-OS is used on network infrastructure, the business concern is availability, not data theft.
Executive priority
Treat this as high priority for network infrastructure resilience. It can interrupt switching or routing operations without authentication, but the sourced impact is availability-only. Remediation urgency is highest where NX-OS NTP is reachable outside tightly controlled management networks.
Technical view
The issue is excessive resource consumption when NX-OS logs drop actions for received NTP MODE_PRIVATE, Mode 7, packets. NTP is enabled by default. The CVSS 3.0 score is 8.6 with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely on Cisco NX-OS devices with NTP enabled, especially where device NTP services are reachable from untrusted or poorly filtered networks. The provided sources do not specify exact affected NX-OS versions.
Exploitation context
The source bundle describes remote unauthenticated exploitation causing DoS through sustained Mode 7 NTP traffic. It does not include evidence of active exploitation, and KEV status is false, so active exploitation should not be assumed from these sources.
Researcher notes
Evidence supports a resource-exhaustion DoS in NX-OS NTP drop logging for Mode 7 packets. Affected versions are not specified in the bundle, so version-scoped conclusions require Cisco advisory confirmation. No confidentiality or integrity impact is cited.
Mitigation direction
- Review Cisco’s advisory for affected NX-OS releases and fixed software guidance.
- Prioritize remediation for internet-facing or broadly reachable NX-OS management/control-plane paths.
- Limit untrusted access to device NTP services where operationally feasible.
- Monitor Cisco guidance before assuming compensating controls are sufficient.
Validation and detection
- Inventory Cisco NX-OS devices and record software versions.
- Confirm whether NTP is enabled on each in-scope device.
- Compare versions and configurations against Cisco’s advisory.
- Review logs and monitoring for CPU, memory, process restarts, or unexpected reloads.
- Check network paths that can reach NTP on NX-OS devices.
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-399: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-1967 mapping review
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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
- 20190828 Cisco NX-OS Software Network Time Protocol 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.