Cisco IOS/IOS XR/IOS XE SNMP Subsystem denial of service

Summaryinfo

A vulnerability was found in Cisco IOS, IOS XR and IOS XE. It has been classified as problematic. This affects an unknown part of the component SNMP Subsystem. Performing a manipulation results in denial of service. This vulnerability is reported as CVE-2025-20172. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Cisco IOS, IOS XR and IOS XE (unknown version). It has been classified as critical. This affects an unknown code block of the component SNMP Subsystem. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

A vulnerability in the SNMP subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR 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. For Cisco IOS and IOS XE Software, a successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. For Cisco IOS XR Software, a successful exploit could allow the attacker to cause the SNMP process to restart, resulting in an interrupted SNMP response from an affected device. Devices that are running Cisco IOS XR Software will not reload.  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.

It is possible to read the advisory at sec.cloudapps.cisco.com. This vulnerability is uniquely identified as CVE-2025-20172 since 10/10/2024. The exploitability is told to be easy. It is possible to initiate the attack remotely. The requirement for exploitation is a authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

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). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS
• IOS XE
• IOS XR

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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