CVE-2019-1967: Cisco NX-OS Software Network Time Protocol Denial of Service Vulnerability

Published Aug 29, 2019
·
Updated

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 MODEPRIVATE (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.

Affected Software

111 affected components
Cisco NX-OS=6.2
Cisco NX-OS=7.3
Cisco NX-OS=8.1
Cisco NX-OS=8.2
Cisco NX-OS=8.3
Cisco MDS 9000
Cisco Mds 9100
Cisco Mds 9140
Cisco Mds 9200
Cisco Mds 9500
Cisco Mds 9700
Cisco NX-OS=6.0\(2\)a8\(9.7\)
Cisco NX-OS=6.0\(2\)u6
Cisco NX-OS=7.0\(3\)i
Cisco NX-OS=9.2
Cisco NX-OS=9.2\(1\)
Cisco Nexus 3016
Cisco Nexus 3048
Cisco Nexus 3064
Cisco Nexus 3064-t
Cisco Nexus 31108pc-v
Cisco Nexus 31108tc-v
Cisco Nexus 31128pq
Cisco Nexus 3132c-z
Cisco Nexus 3132q
Cisco Nexus 3132q-v
Cisco Nexus 3132q-xl
Cisco Nexus 3164q
Cisco Nexus 3172
Cisco Nexus 3172pq-xl
Cisco Nexus 3172tq
Cisco Nexus 3172tq-32t
Cisco Nexus 3172tq-xl
Cisco Nexus 3232c
Cisco Nexus 3264c-e
Cisco Nexus 3264q
Cisco Nexus 3408-s
Cisco Nexus 34180yc
Cisco Nexus 3432d-s
Cisco Nexus 3464c
Cisco Nexus 9000v
Cisco Nexus 92160yc-x
Cisco Nexus 92300yc
Cisco Nexus 92304qc
Cisco Nexus 92348gc-x
Cisco Nexus 9236c
Cisco Nexus 9272q
Cisco Nexus 93108tc-ex
Cisco Nexus 93108tc-fx
Cisco Nexus 93120tx
Cisco Nexus 93128tx
Cisco Nexus 93180lc-ex
Cisco Nexus 93180yc-ex
Cisco Nexus 93180yc-fx
Cisco Nexus 93216tc-fx2
Cisco Nexus 93240yc-fx2
Cisco Nexus 9332c
Cisco Nexus 9332pq
Cisco Nexus 93360yc-fx2
Cisco Nexus 9336c-fx2
Cisco Nexus 9336pq Aci Spine
Cisco Nexus 9348gc-fxp
Cisco Nexus 9364c
Cisco Nexus 9372px
Cisco Nexus 9372px-e
Cisco Nexus 9372tx
Cisco Nexus 9372tx-e
Cisco Nexus 9396px
Cisco Nexus 9396tx
Cisco NX-OS=6.0\(2\)a8
Cisco NX-OS=7.0\(3\)i7
Cisco Nexus 3524
Cisco Nexus 3524-x
Cisco Nexus 3524-xl
Cisco Nexus 3548
Cisco Nexus 3548-x
Cisco Nexus 3548-xl
Cisco NX-OS=7.0\(3\)f
Cisco Nexus 36180yc-r
Cisco Nexus 3636c-r
Cisco Nexus 9504
Cisco Nexus 9508
Cisco Nexus 9516
Cisco NX-OS=7.1\(4\)
Cisco NX-OS=7.1\(4\)n1\(1\)
Cisco NX-OS=7.1\(5\)
Cisco NX-OS=7.2
Cisco Nexus 5548p
Cisco Nexus 5548up
Cisco Nexus 5596t
Cisco Nexus 5596up
Cisco Nexus 56128p
Cisco Nexus 5624q
Cisco Nexus 5648q
Cisco Nexus 5672up
Cisco Nexus 5696q
Cisco Nexus 6001
Cisco Nexus 6004
Cisco NX-OS=7.3\(2\)d1\(1\)
Cisco NX-OS=8.0
Cisco NX-OS=8.3\(2\)s5
Cisco Nexus 7000
Cisco Nexus 7000 10-slot
Cisco Nexus 7000 18-slot
Cisco Nexus 7000 4-slot
Cisco Nexus 7000 9-slot
Cisco Nexus 7700
Cisco Nexus 7700 10-slot
Cisco Nexus 7700 18-slot
Cisco Nexus 7700 2-slot
Cisco Nexus 7700 6-slot

Event History

Aug 28, 2019
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
DescriptionSeverityWeakness
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2019-1967?

CVE-2019-1967 has been assigned a high severity rating due to its potential to cause a denial of service (DoS) condition.

2

How do I fix CVE-2019-1967?

To fix CVE-2019-1967, you need to apply the security patches provided by Cisco for affected NX-OS software versions.

3

What versions of Cisco NX-OS are affected by CVE-2019-1967?

CVE-2019-1967 affects Cisco NX-OS versions 6.2, 7.3, 8.1, 8.2, 8.3 and several other specific releases.

4

What are the potential impacts of CVE-2019-1967?

Successful exploitation of CVE-2019-1967 can lead to exhaustion of system resources, resulting in a denial of service for the affected device.

5

Is there a workaround for CVE-2019-1967?

Cisco recommends disabling the NTP service if it is not needed as a temporary workaround for CVE-2019-1967.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203