Cisco SG350 and SG350X Series Managed Switches SNMP Denial of Service Vulnerability

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco 350 Series Managed Switches (SG350) and Cisco 350X Series Stackable Managed Switches (SG350X) firmware could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to improper error handling when parsing response data for a specific SNMP request. An attacker could exploit this vulnerability by sending a specific SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.

This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMPv2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMPv3, the attacker must have valid SNMP user credentials for the affected system.

Cisco has not released and will not release software updates that address this vulnerability because the affected products are past the date for End of Software Maintenance Releases. The Cisco Product Security Incident Response Team (PSIRT) will continue to evaluate and disclose security vulnerabilities that affect these products until the Last Date of Support is reached.

There are no workarounds that address this vulnerability. However, there is a mitigation.

CVE-2026-20185 — Cisco SG350 and SG350X Series Managed Switches SNMP Denial of Service Vunerability (CVSS 3.1 7.7, CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H)