How severe is CVE-2019-1967?

CVE-2019-1967 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-1967 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1967?

CVE-2019-1967 primarily affects Cisco Nx-os. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-1967?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-1967 published?

CVE-2019-1967 was published on 2019-08-30 and last updated on 2026-06-17.

CVE-2019-1967

CVE-2019-1967 is a high-severity vulnerability in Cisco Nx-os with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Cisco Nx-os
Published: 2019-08-30
Last modified: 2026-06-17

Description

A vulnerability in the Network Time Protocol (NTP) feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to excessive use of system resources when the affected device is logging a drop action for received MODE_PRIVATE (Mode 7) NTP packets. An attacker could exploit this vulnerability by flooding the device with a steady stream of Mode 7 NTP packets. A successful exploit could allow the attacker to cause high CPU and memory usage on the affected device, which could cause internal system processes to restart or cause the affected device to unexpectedly reload. Note: The NTP feature is enabled by default.

Frequently asked questions

What is CVE-2019-1967?: A vulnerability in the Network Time Protocol (NTP) feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to excessive use of system resources when the affected device is logging a drop action for received MODE_PRIVATE (Mode 7) NTP packets. An attacker could exploit this vulnerability by flooding the device with a steady stream of Mode 7 NTP packets. A successful exploit could allow the attacker to cause high CPU and memory usage on the affected device, which could cause internal system processes to restart or cause the affected device to unexpectedly reload. Note: The NTP feature is enabled by default.
How severe is CVE-2019-1967?: CVE-2019-1967 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-1967 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1967?: CVE-2019-1967 primarily affects Cisco Nx-os. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-1967?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-1967 published?: CVE-2019-1967 was published on 2019-08-30 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190828-nxos-ntp-dos

Affected products (20)

cpe:2.3:o:cisco:nx-os:6.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:8.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:8.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:8.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(9.7\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:6.0\(2\)u6:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.0\(3\)i:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:9.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:9.2\(1\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:6.0\(2\)a8:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.0\(3\)i7:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.0\(3\)f:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.1\(4\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.1\(4\)n1\(1\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.1\(5\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:7.3\(2\)d1\(1\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:8.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:8.3\(2\)s5:*:*:*:*:*:*:*

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