CVE-2019-1967

Cisco NX-OS Software Network Time Protocol Denial of Service Vulnerability

HIGH

7.5

CVSS Score

Published: August 29, 2019 at 09:45 PM UTC

Updated: June 17, 2026 at 02:29 AM UTC

92 products affected across 1 vendorNx OSNexus 9508Nexus 93120Tx

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Severity

HIGH7.5

Exploit prediction

EPSS 2%

SSVC

No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nx OS · Cisconpm

95%

v < 8.3(2)6.0(2)a8 6.0(2)a8(9.7)6.0(2)u6 6.2 7.0(3)f 7.0(3)i 7.0(3)i7 7.1(4)7.1(4)n1(1)7.1(5)7.2 7.3 7.3(2)d1(1)8.0 8.1 8.2 8.3 8.3(2)s5 9.2 9.2(1)

Affected range stops below 8.3(2), so it looks safe — our inference, not a vendor statement

cisco-mds-9000 (environment) · cisco-mds-9100 (environment) · cisco-mds-9140 (environment) · cisco-mds-9200 (environment) · cisco-mds-9500 (environment) · cisco-mds-9700 (environment) · cisco-nexus-3016 (environment) · cisco-nexus-3048 (environment) · cisco-nexus-3064 (environment) · cisco-nexus-3064-t (environment) · cisco-nexus-31108pc-v (environment) · cisco-nexus-31108tc-v (environment) · cisco-nexus-31128pq (environment) · cisco-nexus-3132c-z (environment) · cisco-nexus-3132q (environment) · cisco-nexus-3132q-v (environment) · cisco-nexus-3132q-xl (environment) · cisco-nexus-3164q (environment) · cisco-nexus-3172 (environment) · cisco-nexus-3172pq-xl (environment) · cisco-nexus-3172tq (environment) · cisco-nexus-3172tq-32t (environment) · cisco-nexus-3172tq-xl (environment) · cisco-nexus-3232c (environment) · cisco-nexus-3264c-e (environment) · cisco-nexus-3264q (environment) · cisco-nexus-3408-s (environment) · cisco-nexus-34180yc (environment) · cisco-nexus-3432d-s (environment) · cisco-nexus-3464c (environment) · cisco-nexus-3524 (environment) · cisco-nexus-3524-x (environment) · cisco-nexus-3524-xl (environment) · cisco-nexus-3548 (environment) · cisco-nexus-3548-x (environment) · cisco-nexus-3548-xl (environment) · cisco-nexus-36180yc-r (environment) · cisco-nexus-3636c-r (environment) · cisco-nexus-5548p (environment) · cisco-nexus-5548up (environment) · cisco-nexus-5596t (environment) · cisco-nexus-5596up (environment) · cisco-nexus-56128p (environment) · cisco-nexus-5624q (environment) · cisco-nexus-5648q (environment) · cisco-nexus-5672up (environment) · cisco-nexus-5696q (environment) · cisco-nexus-6001 (environment) · cisco-nexus-6004 (environment) · cisco-nexus-7000 (environment) · cisco-nexus-7000-10-slot (environment) · cisco-nexus-7000-18-slot (environment) · cisco-nexus-7000-4-slot (environment) · cisco-nexus-7000-9-slot (environment) · cisco-nexus-7700 (environment) · cisco-nexus-7700-10-slot (environment) · cisco-nexus-7700-18-slot (environment) · cisco-nexus-7700-2-slot (environment) · cisco-nexus-7700-6-slot (environment) · cisco-nexus-9000v (environment) · cisco-nexus-92160yc-x (environment) · cisco-nexus-92300yc (environment) · cisco-nexus-92304qc (environment) · cisco-nexus-92348gc-x (environment) · cisco-nexus-9236c (environment) · cisco-nexus-9272q (environment) · cisco-nexus-93108tc-ex (environment) · cisco-nexus-93108tc-fx (environment) · cisco-nexus-93120tx (environment) · cisco-nexus-93128tx (environment) · cisco-nexus-93180lc-ex (environment) · cisco-nexus-93180yc-ex (environment) · cisco-nexus-93180yc-fx (environment) · cisco-nexus-93216tc-fx2 (environment) · cisco-nexus-93240yc-fx2 (environment) · cisco-nexus-9332c (environment) · cisco-nexus-9332pq (environment) · cisco-nexus-93360yc-fx2 (environment) · cisco-nexus-9336c-fx2 (environment) · cisco-nexus-9336pq-aci-spine (environment) · cisco-nexus-9348gc-fxp (environment) · cisco-nexus-9364c (environment) · cisco-nexus-9372px (environment) · cisco-nexus-9372px-e (environment) · cisco-nexus-9372tx (environment) · cisco-nexus-9372tx-e (environment) · cisco-nexus-9396px (environment) · cisco-nexus-9396tx (environment) · cisco-nexus-9504 (environment) · cisco-nexus-9508 (environment) · cisco-nexus-9516 (environment)

Mds 9000 · Ciscodevice

80%

All versions

Mds 9100 · Ciscodevice

80%

All versions

Mds 9140 · Ciscodevice

80%

All versions

Mds 9200 · Ciscodevice

80%

All versions