CVE-2019-1963: Cisco FXOS and NX-OS Software Authenticated Simple Network Management Protocol Denial of Service Vulnerability

Severity: medium (CVSS 6.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-08-28 · updated 2026-06-17
Weakness: CWE-20

Description

A vulnerability in the Simple Network Management Protocol (SNMP) input packet processor of Cisco FXOS Software and Cisco NX-OS Software could allow an authenticated, remote attacker to cause the SNMP application on an affected device to restart unexpectedly. The vulnerability is due to improper validation of Abstract Syntax Notation One (ASN.1)-encoded variables in SNMP packets. An attacker could exploit this vulnerability by sending a crafted SNMP packet to the SNMP daemon on the affected device. A successful exploit could allow the attacker to cause the SNMP application to restart multiple times, leading to a system-level restart and a denial of service (DoS) condition.

Affected products

Cisco Fx-Os: before 2.2.2.91; from 2.3 before 2.3.1.130; from 2.4 before 2.4.1.222 — fixed in 2.2.2.91, 2.3.1.130, 2.4.1.222
Cisco NX-OS: from 5.2 before 6.2\(29\); from 7.3 before 8.4; before 13.2\(7k\); from 14.0 before 14.0\(2c\); from 14.1 before 14.1\(1i\); from 7.0\(3\)f before 9.2\(3\) — fixed in 13.2\(7k\), 14.0\(2c\), 14.1\(1i\), 5.2, 5.2\(1\)sv3\(4.1a\), 5.2\(1\)sv5\(1.2\)

How to fix

Upgrade to a fixed version: Cisco Fx-Os 2.2.2.91, 2.3.1.130, 2.4.1.222; Cisco NX-OS 13.2\(7k\), 14.0\(2c\), 14.1\(1i\), 5.2. Check the vendor advisory for mitigations.

References

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