Cisco IOS SNMP Vulnerabilities Allow Attackers to Launch DoS Attacks”

Cisco has disclosed multiple vulnerabilities in its Simple Network Management Protocol (SNMP) subsystem affecting Cisco IOS, IOS XE, and IOS XR software.

These flaws, identified as high-severity, could allow an authenticated remote attacker to trigger Denial-of-Service (DoS) conditions, disrupting network operations.

Key Details

According to the Cisco Security Advisory ID: cisco-sa-snmp-dos-sdxnSUcW, the vulnerabilities stem from improper error handling during SNMP request parsing.

Exploiting these flaws requires knowledge of valid SNMP credentials. The vulnerabilities affect SNMP versions 1, 2c, and 3.

Attackers leveraging these vulnerabilities can send specially crafted SNMP requests to susceptible devices, potentially causing unexpected device reloads (in Cisco IOS and IOS XE) or restarting the SNMP process (in Cisco IOS XR).

The CVSS Base Score of 7.7 reflects the critical nature of these flaws for network stability.

Associated CVE IDs include CVE-2025-20169, CVE-2025-20170, CVE-2025-20171, and more, with security impact ratings ranging from Medium to High, depending on the specific vulnerability and affected software.

Vulnerable Devices

The vulnerabilities impact Cisco devices running affected versions of Cisco IOS, IOS XE, or IOS XR software with SNMP enabled. Administrators can verify their device configurations using commands such as:

• show running-config | include snmp-server community (for SNMP v1/v2c)
• show snmp user (for SNMP v3).

If output is displayed, the SNMP feature is active, and the device might be vulnerable.

Cisco has announced that there are no workarounds to fully address these vulnerabilities at this time.

Mitigations, such as disabling specific SNMP Object Identifiers (OIDs), are available to reduce risk, but they may limit device management capabilities (e.g., hardware inventory).

The company strongly urges administrators to implement mitigations until patches are deployed.

Cisco plans to release software updates to resolve these vulnerabilities. Organizations are advised to monitor the official Cisco Security Advisory page here for further updates.

These SNMP-related vulnerabilities highlight the importance of proactive network security measures, especially in enterprise environments where Cisco devices are widely used.

The flaws remind organizations to strengthen SNMP configurations, restrict community strings, and deploy patches swiftly.

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