CVE-2025-20176: Cisco IOS

High severity, CVSS 7.7. EPSS: 0.8% chance of exploitation in the next 30 days.

A vulnerability in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper error handling when parsing SNMP requests. An attacker could exploit this vulnerability by sending a crafted 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 SNMP v2c 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 SNMP v3, the attacker must have valid SNMP user credentials for the affected system.

Affected products

• Cisco IOS: version 15.0(1)sy only; version 15.0(1)sy1 only; version 15.0(1)sy2 only; version 15.0(1)sy3 only; version 15.0(1)sy4 only; version 15.0(1)sy5 only; …
• Cisco IOS XE: version 3.3.0se only; version 3.3.1se only; version 3.3.2se only; version 3.3.3se only; version 3.3.4se only; version 3.3.5se only; …

Published 2025-02-05. Last modified 2026-06-17.