Cisco IOS/IOS XE SNMP Subsystem denial of service

Summaryinfo

A vulnerability labeled as critical has been found in Cisco IOS and IOS XE. The impacted element is an unknown function of the component SNMP Subsystem. Such manipulation leads to denial of service. This vulnerability is uniquely identified as CVE-2025-20176. The attack can be launched remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Cisco IOS and IOS XE (the affected version unknown). Affected by this issue is an unknown part of the component SNMP Subsystem. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability is handled as CVE-2025-20176 since 10/10/2024. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 215126 (Cisco IOS Software SNMP DoS (cisco-sa-snmp-dos-sdxnSUcW)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (215126). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS
• IOS XE

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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